The best part about xbow hybrid is that you don't need to dedicate skill points like you are required to for throwing. Basically, you can afford yourself more ironflesh if you're not attempting to be a marksman or arbalest user. Something like 100 xbow wpf would be fine for general crossbow usage. Often-times the best use for that class is secondary anti-cav. You certainly do not need to sit back and shoot until you run out of bolts, although you could. It is extremely viable to shoot 5-6 bolts at cavalry or infantry, and proceed to rejoin the fight. If you get blackbarred or very low hp, you can run back and continue to contribute without fear.
A crossbow REALLY comes in handy when the numbers are something like 3v3 at the end of a round and one of the enemies is an HA/HX.