Lots of reasons really. No leverage, so there's not enough money in it for me. Can't short them, no futures or options on them, don't behave like real currencies. The price is controlled by circlejerkers keeping it up and amateurs selling it down. Completely newb market, full of people who've never traded a day in their life. Highly susceptible to 'internet rumours', oh man I could go on... lolol.
I can trade options on 6 major coins at the moment (with my current broker) but because of the high volatility the spreads are extremely wide, just not worth it. Example BTC is 70 minimum, when it's really quiet. So just opening a BTC trade I need it to move $70 dollars before I'm even in profit. That can take days to move that much... By comparison my FX spread is typically 0.4 and it can move 5 times that in a single tick.
Yes you can. The guys in the Crypto Traders group do it all the time. You can leverage 100x on Bitmex. Bitcoin has moved over 300 dollars today. It moves back and forth way more than 70 dollars every day. I'm not sure where you're getting your information.
I think I'll stick with my current broker, I've been with them a long time and trust them with my money. Not prepared to put money in another company that could go bust tomorrow. Crypto companies don't have a great track record... :-)
Maybe when mainstream financial institutions start offering products to trade as a matter of course and there's proper liquidity in the market. At the moment it's more like an emerging market, or penny stocks, junk bonds.