It cannot be bad advice because learning something even slightly valuable is always good in a vacuum (as you mentioned) Since he has not given any reference po

It cannot be bad advice because learning something even slightly valuable is always good in a vacuum (as you mentioned) Since he has not given any reference point it is equally as good advice as „just learn everything slightly valuable“. So the real question is: „What should I not learn in favor of learning this.“ Or in other words: His comment is not usable because it can mean anything or nothing.