Bitmex might be the one in the spot light right now, negatively speaking, but this will eventually affect other non compliant derivative platforms too. It's either you bullet proof your platform against US residents from the start, or you will be held accountable eventually for providing a service to US residents initially, even when you exclude US residents later on.
if they allow people from the USA and there's decent liquidity, i'll be all over it. i hate doing the VPN thing with bitmex et al.
but you're right, i don't understand why they would risk that legally considering the nature of the CFTC bitmex probe. then again, kucoin hasn't restricted americans from any token markets despite binance, poloniex, and bittrex all doing so. americans can only hope they keep being this lax for as long as possible.
I'm pretty certain that when Coinbase enters the leverage game they will experience a massive boost in actual use. Currently people mainly use Coinbase as fiat gateway to enter or exit, but this is something that will keep people within their ecosystem. The good thing here is that they legally aren't allowed to offer anything near 100x leverage. I assume it will be 2-5x at most, which is plenty enough.
they (gdax) used to offer margin trading up to 3x leverage. they removed it after a flash crash. it was always restricted to accredited investors anyway and i'm guessing they would apply those restrictions again since they are so uptight about compliance. so that would cut off most retail traders anyway.