As of now, your profit will be in fiat as that is the standard medium, channel or instrument to your purchases in your daily lives. Some wallets offer bill payments which you can pay in BTC to pay your liabilities, so in that aspect you might not need to turn it into fiat cash. Although these services are offered in some wallets, you can't rely on it much as you're still limited on what you can do to your crypto coin. Wait until country fully adopts its flexible use in our daily lives.
Do use Tether as it should be stable?
You can use tether somehow if you're aren't sure about the security of the profit you have currently in your wallet. Crypto prices swings so you might need it somehow, but I still suggest to turn it into fiat first. Let the security of the digital money develop more.