Well thats double sword, if Switch dont have dock and Joy Cons and same price point, also wouldn't go as nearly well. So point is about hybrid concept, not just about one thing.

Right but if it was just the handheld, it'd do better then if it was just the home console.

It's a two-edged sword, but Handheld is the more important edge.

If it didn't have the handheld aspect it's potential would be much much less then it is now. Nintendo can't compete with PlayStation/Xbox in the same home-console space, they need to create their own. Which is evidenced by the Wii being the only very succesful dedicated home-console from them since PlayStation joined the market. The Wii being unique rather then a direct competitor allowed it's success.

True, but in this case here we are talking about $300 only handheld, remember, 3DS start selling good just after price cut to $170.

apart from it's 3D gimmick the 3DS also had super weak HW even for the time it released in, while the Tegra X1 in the Switch is the most potent chip (GPU wise) actually in use for a mobile device of it's size class

From time to time I saw this point from some people, saying that Switch is doing great because it's handheld and every Nintendo handheld had great sales, so its same for Switch.

But those people missing few facts what made Switch difrent compared to other Nintendo handhelds:

-Switch is a hybrid, its handheld and home console in same time. Definitely it's not best fit like handheld because it's bigger and dont have very good battery life either.

-Switch has price point of Nintendo home console, not Nintendo handheld. Just look at launch prices of last few Nintendo home consoles, GC had launch price of $200, Wii of $200 and Wii U of $300 (it had version of $350 also). 3DS had launch price of $250 but it didnt sell very well, and start selling great only after price cut to $170 that received only 6 months after launch, while Switch is selling great with $300 and actualy Nintendo still cant keep up with demand.

-Switch games have price point of home console games, not of handheld (Switch AAA games are $60 same like they were for Wii and Wii U, 3DS/DS AAA games are $40).

So with those facts on mind Switch position on market is more like home console than its like handheld, despite fact that it can be used like real handheld also.

So no, Switch is not selling great because it just another Nintendo handheld and they always sell well, Switch is selling because great concept, great system seller games and good marketing.

But i wouldn't use price as a big factor.
You see, if you say that "Switch has price point of Nintendo home console" as a rebuttal, you need to remember that 3DS was priced exactly as the Wii (it was 250 and not 200, as you wrote). Yet, you wouldn't say 3DS was a home console, would you?

Switch having SW price points similar to home consoles, might not be the best argument either.
First, i have seen prices for 3DS Nintendo games, between 45-50. 
Second, i haven't it's known that Switch's cards are more expensive and have caused games to be higher in price (Rime, comes to mind).
Third, i think it was just a matter of time until even handheld games saw a price surge. You can't continue to spend more money in developing more expensive games and not have that reflect on games' prices.

To me, Switch is a hybrid, but even then it's more of a home console because that's where it's strongest at.
As you mentioned, it has a weaker battery, bigger dimensions than what a handheld could offer.