Usually you earn tokens worth very little with airdrops (but you don't need to do actual work). Bounties it depends, I have earned very little sometimes (worthless) or I have been pleasingly surprised with more than USD 500 worth of tokens. I only do bounties for projects I like and invest myself, it is a way to earn more tokens you like on top of your investment, like the cream on top of the pie.
agreed, More than that is Most of the bounties are launched by ICOs that's means those bounties are behind various projects, so the profits could be huge if you hold your coins that you get in bounties, but in airdrop most of them Fails and have no purpose, are shit coins , so its better to get in bounties, but there Few airdrops who can be succcesed