Haha, I think this is a good idea.
This is like throwing the kid into the deep end.
Let them get touch/feeling as early as possible.
I can swear that many adults who has been playing for years won't be able to use that mini bat.
But I won't start the kids with this, I would still start normal, and maybe for fun session to get them to experience this a bit more.
Speaking about that, I'm going to organise a few for my students!