The main gimmick is being able to play "real" 3D console games like Zelda: BoTW, Skyrim, NBA 2K, Splatoon, Mario 3D, Xenoblade, hardcore Japanese RPGs anywhere with a visual fidelity that most people have associated with home consoles up until now. Certainly it's the most powerful portable gaming device ever made by a mile. 

So yeah the main point of appeal is to someone who is already an experienced, selective gamer, not "soccer mom's first console", or "Nintendo's smart phone killer gaming device". 

That all depends on how you define a casual gamer. I certainly wouldn't consider every person who knows how to use a traditional controller a "core" gamer.

A core gamer is an informed gamer. A casual gamer is someone who only plays games casually and is mostly uninformed about the games industry. Casual isn't restricted to people who like motion games and mobile only. So yeah, I'd say Switch does target casuals.

A person who plays games casually, as in something they do while relaxing in their free time or while hanging out with friends.

Case in point, you think casual means soccer moms and people who play free mobile time wasters.

That is the reason why 3 party games din't sold very well on the Wii.

Basically the way I see it is this

Joy-Con is the natural evolution of the Wii Remote similar to how the SNES controller was the natural evolution of the NES controller.

I mostly consider a casual gamer as someone who gets their gaming knowledge from TV's commercials or seeing a friends system/game and going "oh, that's neat. What's that?"

People online bitching about FPS, graphics, power, price, ect are not casual. And I'm sure if you were to ask a mod or owner of this site how many people are this site, it is but a fraction of a fraction of the total gamers out there.

"Core" gamers are the minority.

Will Switch's gimmick (people love to label Nintendo things condesendinly gimmicks don't they?) attract casuals? Very likely initially at least. All it takes is someone to see another on a bus/train/lobby or somewhere playing Mario Kart, Zelda, Skyrim or something on their Switch for the other person playing Clash of Clans to be intrigued/jealous and want that.

The Wii sold gangbusters on that word of mouth/try it out, ect. People had a blast playing Wii sports at a firends and so got it. I'm guessing the initial draw of the Tablet playing great games portable will attract many. It all depends on how long that lasts. Nintendo needs ot keep games pumping out that are fun to keep the tablets in the wild for others to see and want them.

So this is my message to all Nintendo people who want the system to "win". PLAY IN PUBLIC. Don't be ashamed of playing a Nintendo game in public. Be loud and proud with your system. People seeing you playing is free advertising for Nintendo. Now when those "region free" Waifu games come out, then maybe stay hidden again.

Good. You can't rely on filthy casuals.

That can be literally 95% of the industry, lol. 

There's a difference between a soccer mom who's extent of gaming ability is Angry Birds on a phone or Just Dance, and she'd never be able to complete a game even like Mario 64, and someone who can play Mario 64 just fine, for instance. 

Drawing a dilineation there isn't incorrect, because it's significant, those two audiences are not one and the same. I would more accurately the industry falls into 3 rough pools with some overlap but not a ton ...

Pool 1 - A person who doesn't really care that much about gaming, likes to play once in a while to burn 10-15 minutes at most a day except for that one time they got hooked on Candy Crush and played for 4 straight hours and thought that was an impressive feat. Mostly plays on smartphones/Facebook browser, doesn't like complex games, virtually any type of 3D game is beyond their abilities or interest. Even after 6 years of having a Wii that they played intermittenly, they still wouldn't be able to get even 1/4 of the way through a game like Ocarina of Time even with a gun to their head. 

Pool 2 - This person can basically play any type of game you put in front of them, generally have been playing games since childhood, but they prefer the 'mainstream' games that appeal to their specific real life interests like Call of Duty, NBA, Madden NFL, GTA, Forza, Halo, etc. They prefer to play with friends too. They don't follow the industry closely or at all in most cases. Just wanna have fun, but have a relatively high level of skill, given enough time/practice they would be good at any type of game. Gaming is more "wish fulfillment" for this crowd (I wanna be a sports star, gangster, super soldier, X-Wing pilot, that's cool). 

Pool 3 - Hardcore gamer, they understand industry nuances like the difference between Japanese and American games, keep track of developers and even know the designers of games. They are the wine connosieurs of gaming and early adopters for most/all platforms, they are quite picky in what they will and won't play. Oddly this crowd inadvertantly often becomes the actual buying audience for games like Splatoon because only they can appreciate certain aspects of that game, whereas Pool 1 will shun the game for being too complex and Pool 2 will shun the game because it doesn't allign with their "I just want badass fantasy fullfilment in my games". 

And then you have Pool 4 which is kids ... they are drawn to just about any type of video game like a fly to a light (especially boys). But by age 8/9/10 or they go into either pool 2 or 3 (ie: wanting to play GTA because the older kids at school think it's cool, or loving games so much that they become Pool 3). 

The problem is how casual is defined. In The Playstation and Xbox communities casual is defined as someone who buys a Call of Duty game every year and occasionally picks up 1 or 2 other dude bro games. In the Nintendo community, casual defines someone who wants to play a mario game and maybe a round of Wii fit. Problem is, since the Wii U we've seen casuals become more and more fixated on the first option than the second. I think it has to do a lot with a demographic shift, the parents, grandmas, and girls who bought the Wii aren't fixated on gaming so they've moved on. Call of Duty gamers are at least consistent in their needs. The Playstation 4 is 90% a casual audience.