"Use subclasses over enums" must be some niche advice. I've never heard it. The youtuber seems to be referring to some specific example (he refers to specific advice from "them") so I guess there's some context in the other videos of the series.
re: the speedup from moving from subclassing to enums - Compiler isn't pulling its weight if it can't devirtualize in such a simple program.
re: the speedup from replacing the enum switch with a lookup table and common subexpression - Compiler isn't pulling its weight if it can't notice common subexpressions.
So both the premise and the results seem unconvincing to me.
Of course, he is the one with numbers and I just have an untested hypothesis, so don't believe me.
re: the speedup from moving from subclassing to enums - Compiler isn't pulling its weight if it can't devirtualize in such a simple program.
re: the speedup from replacing the enum switch with a lookup table and common subexpression - Compiler isn't pulling its weight if it can't notice common subexpressions.
So both the premise and the results seem unconvincing to me.
Of course, he is the one with numbers and I just have an untested hypothesis, so don't believe me.