I think both sides of the coin on the issue of durability are right, it just kind of depends on the kids in question.
First of all, the $70 asking price includes the software, which is probably anywhere from $40-$60 in and of itself given this is Nintendo we’re talking about. The cardboard stuff will probably packaged separately and for much cheaper, although again with the Nintendo probably not cheap enough.
If what they’re saying is true, and the game is playable without the boxes, then it doesn’t seem like that bad of a deal if it the game is fun by itself. It’s better than buying some fiddly plastic thing for the same price and being SOL when it breaks. Some kids will treat this the right way, some won’t, and you probably know your own kid well enough to predict the future for it.
The world of kids toys and what people are willing to hand to children is baffling and has no consistent internal logic. I’ve had friends talk about how their kid will destroy this thing in minutes, meanwhile they hand their kids a $600 iPad without a second thought. I’m probably making wildly inconsistent choices for my own kid as well, so I’m not judging, it’s just fascinating to see what other people consider dealbreakers versus yourself.