Shorting is notoriously difficult to do. You might know the right trend, but If you mess up your timing you can still lose money.
Exactly that's the risk that is amplified to an extreme by trading on leverage. The vast majority of all traders loose money. It's not worth to risk capital and mental health in such a game.
Shorting Bitcoin is even riskier, because the market often moves unpredictably and extremely fast. The volatility is very high. Doing that leveraged is insane.
ya.ya.yo!