BH is one of the best comeback heroes in the game only surpassed by someone like NP. I can't tell you how many times Navi has come back from a large deficit thanks to getting some clutch Track kills.I hate bounty hunter, one of the hardest heroes to play well, also a very situational pick. He needs to snowball, he needs to gank, he has to dominate early to mid game because he falls off late game.
You draft BH for the offlane, for early ganking, to counter some invisible heroes and to gain a gold advantage. He's a great hero to pick if you feel like you are against a well matched opposition. He doesn't "need" to snowball, he definitely needs to gank but that's all he needs to do along with scouting. He doesn't need to farm creeps because he farms heroes.