I think it is important at any age. I've been reading on a Kindle or iPad for years. My daughter recently bought a physical book for me and I had a hard time reading it. I've never had a difficult time diving into a book, but reading a physical book after using a kindle for so long made immersing my mind into the book quite challenging for some reason. I bought some other physical books the other day to see if the issue was just the story I was reading or if there is indeed an aspect of reading physical books that has atrophied in my brain after using electronic books for so long. If the latter, that would be quite concerning to me.