Children on screens versus children with books

[Belle]

I've been engaged in a discussion about this and I commented that my son's two children are not allowed to use screens but have to read books; they get screens elsewhere with their mother. And both children are chomping a path through childrens' books at the local library - with all the imaginative illustrations. This is what a university Professor wrote to me and I'm wanting to solicit comments here - (not my 'children' but grandchildren):

Glad your children are enjoying reading. BUT, when you are reading you have to sit dead still for hours on end - a kind of catatonic state - that is certainly not good for the eyes or for the general physical condition of a growing child’s body (or an adult’s for that matter). I find myself stumped… how on earth can reading books be held up as a preferable health alternative to watching TV and using a computer or electronic device? Crazy! At least when you’re watching TV you can move around a bit, get up during ad breaks etc. but when you’re reading books? Nope… gotta stay dead still hour after hour. But books have a kind of fetishised cachet in our society. They may be good for the mind, but they’re downright unhealthy for the body.

This man assumes that children are reading challenging material like a novel on their screens; the fact is that the vast majority I've seen are merely playing games and flick, flick, flick.