I would think it is a good thing. The only people this doesn't encourage to buy Switch is people who own a Wii U, and my guess is Nintendo believes it has those 13 million or so customers in the pocket already. A steady flow of games for the system is what Nintendo needs to get people who rejected Wii U on board.

Cannibalising the Wii U library is a quick and cheap way of substantially increasing the game library in a way that will encourage a larger market segment to get on board with Switch. As long as brand new games are released as reasonable intervals I suspect the die hard fans will be happy.

1-2 Switch, Snipperclips, ARMS, Splatoon 2, Mario Rabbids, Fire Emblem Warriors, Xenoblade 2 and Mario Odyssey, so there is plenty good Nintendo games in first 10 months of Switch even for Wii U owners. Only Nintendo Wii U ports are MK8D and Pokken Tournament DX, while Zelda BotW is brand new game with dual release.

Switch battery life is similar to launch 3DS battery life. You can't expect much battery life for 6.2" that plays full home console games, at least 8 hrs battery life is not realistic at all today, last few handhelds have better life max of 5 hours. Maybe we could have up to 5 hrs battery with Switch Mini/Pocket that could be used just in handheld mode, but hardly above 5hrs. Also comparing Wii U gamepad and Switch doesn't make sense, Wii U gamepad was just streaming device, while Switch has hole hardware (CPU, GPU, RAM...).

Reasoning is very obvious, Wii U is biggest Nintendo fail with terrible sales but had some great games, so most of future Switch owners didnt played them, also Switch offers full handheld mode compared to Wii U, so totally make sense to port some good Wii U games (even some 3rd party games), its easy profit for Nintendo, while plenty of people who didn't had those games will be able to play them, some Wii U owners will do doulbe dip beacuse of full handheld mode, and Switch lineup of games will be stronger and more diverse in any case.

Ports are cheap and they can be done in months, so it's not like Nintendo could do new game or new IP for same time and resources they are spending on porting. And its not about Nintendo only, Sony and lots 3rd party doing same thing, even PS4 that dont have full handheld mode and where on PS3 much more people were able to play some of great Sony games than people were on Wii U. Sony ported TLoU, Uncharted 1, Uncharted 2, Uncharted 3, GoW 3, Journey, Heavy Rain, Beyond: Two Souls...

Few people owned a Wii U. Porting it's games to Switch allows those people who didn't own one to enjoy those games. Simple really. One thing that really REALLY sucks about Saturn and Dreamcast is there is hundreds of games that never came to anything else and it's a shame as there is some real great stuff most people missed.

Switch still needs Tokyo Mirage Sessions #FE,Xenoblade Chronicles X. I think it's a given at this point Bayonetta 1+2 & Wonderful 101 are coming to it.

I have a Wii U but no Switch btw.

It's good for people who never owned the system. Since I own both the WiiU and the Switch, I want new games. I can't think of one WiiU title that I want on the switch.

A good thing for people who havent bought a Wii U but not for me. I really dont see any reason yet to get a Switch like at all, i havent even really utilized my Wii U yet, like all these Switch games i can get on my Wii U. And its not like these remasters run that much better on the switch unlike it is with Xbox One and PS4.

It's obvious that they want to bring wii u games to switch so they can make some money off of them since they didn't on the wii u but we don't know the rest of their reasoning behind the choice if there's more. Because nintendo doesn't have much of any 3rd party support, this could be easily a case of nintendo really wanted to fill in some of those gaps in between their major releases which is fine I guess. I think it does tie up their studios that could be used on something else. 

I don't think you realise how much work porting requires. If you look at the amount of ports coming to Wii U Deluxe... I mean Nintendo Switch my bad, then you can certainly say it sacrifices significant time and manpower for new high quality games. Even if you never had a Wii U, just buy one and get all the games without any obvious downgrades and at a much cheaper price and a much bigger library. 

I think I was very clear about reasons: easy profit, more diverse and stronger lineup of games (filling gaps comes with this point). Its win-win situation in any case.

Ah yes that dizying mountain of 2 ports from Nintendo and their direct partners is just a diabolically CRIPPLING strain on their resources.

Nintendo has far more new 1st and 2nd party offerings coming to the Switch in its first 10 months than ports.  Zelda (crossgen, not the same), ARMS, Splatoon 2, Fire Emblem Warriots, Mario+Rabbids Kingdom battle, Super Mario Odyssey, and Xdnoblade 2 are all retail new first and second party offerings in these first 10 months.  And that doesn't include Bomberman, which is a third part exclusuve.

What third parties do is mostly beyond Nintendo's control.

Whatever version suits ya, I don't care. Still, we don't have access to nintendo's inner workings.