If you find a very good project that is also promising and has good ideas, bounty is worth doing because at the end you get free token as reward for promoting the projects and the amount of token you get depends on your rank, the allocation and the number of participants in the campaign. Personally, I spend 3 to 5hours of my day doing bounty because I do several of them and need to complete the task for the day and this doesn't affect my daily activities.