Oh I see. I thought by "making your bars lower" you meant making your bars lower
(ie. lower/shorter stem and/or less stackers)
Rolling them back will help with streety lines, as you meant - I just got the wrong end of the stick.
It also won't make the bike any worse for trials-trials. I used to have my bars' rise pointing in the same direction as the stem's shaft.
Rolled them back to see how much easier it would bunnyhop, and whilst it's better for them, it's no worse at all for sidehops/gaps/tech lines etc.
I find further forwards is only good for trials-trials, where as further back is better for everything (with no ill effect towards trials-trials).
I have Monty 221 risers set at about halfway between being perpendicular to the floor and the angle of my headtube.