Tried both on same account for couple of months each. Didn’t notice any difference in reach. I am now just posting them in the caption seperated by couple of blank rows.
They work in the comments provided you post them immediately. There is probably a window in which to post them, however it isn’t an easy one to miss. They 100% work when posted in the comments section.
I have done both and never noticed a difference, that advice was probably just a hoax to seem more authentic and provide something that has not been said before