Even a one year old baby needs a variety of different "play". She will enjoy playing with you, and it is an opportunity to help their development in all kinds of ways. But I always felt that if they were content sitting playing by themselves for a while then I certainly left them to it.
Learning to amuse themselves is a very useful skill for all children to learn.
Some children need a lot more attention than others though - you just have to follow their lead.
Our Welfare State. Is it broken?