It's something of choice and personal reasons. Bounty are reward paid for your service, it's now left for you to keep it or sell them whenever you receive them.
Though, I do keep in the past but I'm a bit afraid of Btc dump especially now that we are having a new all time high. If I get paid in Btc, I can hold for some period but sell when I receive payment in Altcoins.
Altcoins don't perform better when Btc is dumping except the project is of high quality foundation with enough hype.