Is prioritizing developing these skills good for a child’s overall development?
I could easily be biased though: much of my adult life has involved reading large quantities of material and writing much shorter quantities afterwards; if my life were not text-centric I might've viewed the early start and subsequent advantage as a waste?
(being in the habit of reading for years before you get there also makes elementary school far more bearable, as you have time free to think your own thoughts while the rest of the class is still finishing the assigned reading)