(I also have aphantasia and find it extremely difficult to believe that the entire thing isn't just a misunderstanding of language.)
Why wouldn't you lol
It's not useless information - I get to track what I ate when, I get to figure out the recipe if I like something etc etc. Imagine going "What you had for breakfast is useful information" as if your brain isn't already full of useless information.
> at least until their brain fills up.
(X) That's not how it works.
>If I don't, it's gone.
As I said, for the rest of us, it isn't an issue. We just remember. You don't - so you just go "it's useless information." It's not for us.