A cleaner idle..lol
Better gas milage.
More power,earlier, same power up top.
Improved throttle response.
Just lights it earlier aiding in a more complete burn. Less residual when the over lap let's end gas linger or revert and contaminate the intake charge at low speed under the cam range. Improves everything under the cam range.
Every engine combo coupled with tq convertor,weight,gear will want it's own curve and let you know how early it can take it.
My stuff has always ran 24-28 initial timing with 4-6 degrees mechanical all in by 2200
The more radical the cam the more the effect it will have. What it wants or positively responds to...is the ticket.