I could read before 4 too, but there really is no point and it has nothing to do with intelligence. Reading is a skill. In fact, there are plenty of school systems that advise not to read before 7, because it immediately takes away from other skill sets like memorising and imagination as soon as a child can read, according to some. Steiner schools have that principle for example. Or Waldorf.
We live in a country that has this approach and we hate it. I didn’t have an opinion on it beforehand but now I’m like nope, this
tit does not work. Our family knows multiple (admittedly newly) 8 year olds who cannot read and write without assistance - that’s too old!
I actually find lack of literacy to be barrier to creativity and imagination.
It’s not a matter of intelligence; it’s a matter of opening doors: new experiences, points of view, moments in history, etc. I can’t imagine having to wait until 8 years old to experience my favorite literary characters one-on-one. It feels heartbreaking, which I know sounds dramatic! It also builds vocab and sequencing skills, just to name a couple, so there’s definitely a lot of logic behind getting a head start.
It’s also, as you say, an extremely important skill to be a confident and accurate reader - emergencies, online learning, if they god forbid get lost etc.