Hops added in active fermentation go through the biotransformation process and can develop unique and more intense flavors. Aroma definitely suffers compared to dry-hopping after fermentation has stopped but the flavor contribution is much better. I think of bio-trans hops as being in-between whirlpool and dry hops, giving more flavor than the latter and more aroma than the former and producing a somewhat unique and enhanced expression of any the hop combinations.
Since my current IPA is using hops mentioned in most Pliny clones, I'm sort of eager to do a batch that utilizes hops at all post-boil stages - whirlpool, bio-trans, dry hopping in the fermenter before and after cold-crash. That ought to check all the boxes.