It seems to me that both sources of income can bring good profits. The bounty were profitable 2 years ago. At the moment I prefer to trade, because it brings me more profit than the Bounty.
If the bounty project you are participating does not pay after the bounty campaigns overs, what will you do? Go to scam acussation board see the multiple reports filed by the bitcointalk users. Then you will not say bounties are profitable.
Trading is profitable if you use all your skill or using bot to fix the trade. Else here also we cannot survive for longtime.