Yes, for some people, its can be the main job. like my uncle, he retire from popular bank in my country, he got salary $300 in a month. but he has legendary account that can give him up to $2000 in a month from signature and translate campaign. he join bitcointalk from 2014th.
But for me that only have member account, bounty campaign is my spare time job.
Like my brothe in the comment below :
It's very good advise for beginner in the world of bounty hunter. we must have financial backup in order to prevent mis payout by some unsuccesful and scam project that already we participate