The WiiU had quite a few absolute must play titles there were exclusive to the platform. Over the last 3 years though, many of them have been ported to the Switch or PC. Now that isn't to say the WiiU has no good exclusives left, I think it still does, but that list has grown smaller over the years. I also don't think it's unreasonable to see ports of things like Pikmin 3, Xenoblade Chronicles X, Super Mario 3D World come to the switch at some point in the future. There are also a couple of things like Zombi U, Devil's Third, and Nintendoland that I'm more doubtful on getting a port, and may be WiiU exclusive for a long time.
I picked mine up a few years ago for $80 and still get use out of it. I just really love having a single machine with HDMI that is capable of playing most of the Nintendo back catalog with excellent compatibility. Only N64 and DS are kind of hit or miss, and even then, it's pretty decent. You need homebrew to unlock the full potential of the thing, but that's either free or at least very cheap if you opt for Haxchi.