hold your bitcoin until it becomes worth a shit tonne, then invest. Otherwise you'll lose in terms of btc price. Every time BTC goes up in terms of USDT, the underlying alt coin depreciates.
You are so right here Ive witness just this . I have TRON and bitcoin and every time bitcoin is up TRON is down. Im now taking my money out of TRON completely because I feel like bitcoin is going to stay good for quite some time