YABVU
We have a family iPad which DS (nearly 4) probably uses the most. It was bought for him (!!!) by his Life Guardian but I don't see any need to have several of them, one is enough.
We live in America so long haul flights it's another thing to keep him entertained (as well as books, colouring, a bag full of crap individually wrapped to occupy for longest time). We also do long car journeys too and know if we have one coming up we don't let him use the iPad for about a week before so it's novel again when he gets his sticky paws on it and it does keep him happy on a boring car journey.
Definately doesn't inhibt his imaginative play! I think he probably spends 1-2hours a week on the iPad (obviously not all in one go) and the REST OF THE TIME in imaginative play...he's currently using his toy kitchen as a launching pad for spiderman....who is made out of a toilet roll tube.
Also, they are much more interactive and help imaginative and learning than say the tv (which he also watches, shoot me).
Have to admit to occasionally letting him play when we're out for lunch - very rarely because I agree there's no point in him being there, but sometimes he's overtired and agitated and it keeps the peace for 10mins.
I take it, OP, you don't have one? Therefore don't judge til you know what you're judging....