If you want to buy and sell coins for sure everyone will suggest you use the site: (crypto exchange), including I also recommend it.

However, if you have tokens from the bounty proceeds to sell, and can only be sold to certain wallets such as Etherdelta, Trust wallet etc, of course you should exchange it directly there into Ethereum, after that you just transfer it to an exchange to buy certain coins for your investment.

This is different from cash you have to buy coins, if that's what you want to do of course (exchange crypto) is the right choice, of course it's also a matter of cheaper fees.