I actually think I'll pick this up. The variety pack looks pretty cool. Mostly excited for the piano, the rc cars, and the house that has you playing mini games.
I think people knock Wii Music mostly because it was an E3 reveal and they spent a ton of time on it. They're right to knock the game (although I've never actually played it) because of this fact alone. It was awkward and left a bad taste in people's mouths. On the other hand, Nintendo Labo was announced today (with no mention or leak whatsover before) and will release in 3 months. That's almost no build up at all, and it's apparent that this isn't a "direction" that Nintendo is heading in, but rather an aspect of what is possible with the joy-con/Switch modular capabilities.
I expect this to sell at least a million on the curiosity factor alone. I don't think the main audience will be kids, but rather the 20 somethings to 30 somethings that enjoy Nintendo's more innovative/wacky side. The kids will certainly follow come holiday season, especially if there's good buzz at launch and from critics.