I said in the reveal thread for it, but this thing will either be a success or failure by what the quality of the games that it comes with are imo.
If the games that it comes with are just mostly shitty minigames like it seemed most of them were in 1-2 Switch, on top of being charged $70-$80 for, I can see that completely ruining the whole thing. Don't forget Nintendo charged $50-$60 for 1-2 Switch as well so it's not like they haven't done it before.
If the games/minigames/activities that it comes with for each build set are actually pretty good or at least mostly decent/good then I think it will do well. If they end up being shit then that will ruin the whole thing, why bother buying it to play a game that isn't even good.
But then again I think they did show pictures as well where you can use them with games like Mario Kart 8 Deluxe so it doesn't seem like it's only limited to minigames, so perhaps that will be enough for some too.