I think people often overestimate the effects of these things. It absolutely works for muscle growth but it's not like a steroid or something. Similarly there is enough evidence to suggest that it actually does have some small effect on cognition; I remember a study 10 years ago showing that in people who are creatine deficient (vegans) it improved cognition scores. But it's not going to be a huge effect for someone whose not deficient in some way.

It would actually make sense that as you age and eat less you might get creatine deficient so sure. I don't think it's bullshit, but it's not going to be a huge noticeable effect either.

All of this reminds me of people who don't weight lift "because they don't want to get built." They somehow think you lift some weights and boom you're looking like Arnold. No, it doesn't work that way.