Every person has their own choice in trading and things that are good for me do not mean that I will also be good for everyone. Everyone follows their strategy and makes a choice which is best for him or her. We will just give our opinion to you and the choice will be yours. USDT is a stable coin and did not suddenly but is stable and did not change, if you are seeking stability find a stable coin and less chance of loss USDT is best but remember that it cannot give you high profits as BTC did. While in the other hand, BTC is not a stable coin and is very volatile instead if you choose BTC there is high risk but the more the risk the greater the profits.  Now it is to you what you want to select but my suggestion is Bitcoin if you do want to waste your money and time then invest in the n bitcoin instead of USD