I wouldn't trust Tether to hold as long term "investment". But when you go in and out of trades fast it's not that important imo. Fundamentals only matter on the long term.
I don't use Tether myself since there are better alternatives available. For example Trueusd.
Options are also a good alternative to hedge your long positions with. In the stock market, al lot of professional traders use them. Since they are a way to do cost base reduction. You can now trade Bitcoin options on Deribit:
https://steemit.com/bitcoin/@niel96/how-to-trade-bitcoin-futures-and-options-with-deribit