I don't think reading books is damaging to cognitive health, it's not a passive experience and requires significant energy. I think we'd be hard-pressed to find anyone who could disagree with the benefits of a child reading for multiple hours a day?

I could, if it comes at the cost of socialising.

I spent a lot of time reading as a kid, and very little time with others. Bad socialisation can cost you dearly.

Also was often reading in poorly lit areas, not great for eyesight.