Most other playbooks can take gigs with advancements, and an MC may give moonlighting/gigs as a love-letter when the fiction calls for it (Harholder hires you to guard his holding...)
Think of them as jobs/missions the pc and or crew does in down time for barter or obligations.
Example; Player works bodyguarding and doing murders for the gigs.
Now, you talk with the player about how they work them, then work out the outcome...
depending on the Moonlighting roll Player rolls 7-9 on the above 2 gigs; picks success on body gaurding, fails at do'in murders;
"So Bishop, who are you bodygaurding, then who you killing?" player; "Well, Five-alive is going to bigtown and needs my protection... but his rival Stumps wants him dead... after we get him there, I'm going to take him out!"
2 ways to work this out in game;
1. After the fact... "well you got him there, and as you snuck up behind him to kill him later that day, you get caught right before the act... You kill em real good, but in the skirmish you suffered 3 harm!(embattled), fin.
2. Play it out; "well you get there with Five-alive... you sneak up on him that night like you planned, but... he's ready! - he and his goons appear in the alley, knives out... what do you do? (embattled).
as you can see #2 can take a bit longer, but can give more story opportunities
Hope that helps.
Hankle : )