C.Z.
I successfully used a PNP for play from early on. Before she could sit up I would give her "tummy time" in the PNP if I needed her to be safe while I did some household chore. At first she would only be happy for short spurts of time. Over time, and as she learned to sit up, she would spend much longer periods in there on her own. This helped me a lot as I would keep her in the kitchen with me while I cooked, did dishes, etc. I put toys and books in there with her and played a CD (she likes music). She got used to it and is very comfortable in it even still (she is 15 months now and walking). My recommendation is to start them out early in the PNP - otherwise they might reject it later on if you wait to introduce it when they are older.