To macerate or not to macerate?

[tchib]

I've gotten identical (to my palette) results from maceration and boiling fresh out of the packet. I boil on-grain.
I can understand why maceration and then filtering the macerated liquid into a pot for distillation off grain would be important but boiling on grain seems to yield the same results no matter how long I macerate. Arguably worse tannins on a maceration followed by a boil without filtering.
Does a wise person on here have an explanation? Preferably with some science to back it up?
Peace
T
Clarification: I'm using the term on the grain to describe distilling with the botanicals inside the boiler. Perhaps the wrong term but it stuck.