Yeah, that makes sense. Something I found out, although I don't know if it's true, because I haven't looked into it myself, is that the right Joy-con's IR sensor will be used to detect what's going on in side the boxes. Of course that only applies to certain Labo games/products, but still, it seems cool.
I'd consider purchasing it if one of the games really interests me, but at the same time, I'd rather invest in a pro controller, or an extra set of Joy-cons.