I recently sold my little stash of BTC because I just realized that I don't understand at all what is happening regarding BTC, why it is happening, and whether it will continue to happen. All this BTC has no where to go but into other prospective wallets. I also had a sudden concern that there is no reason to trust Coinbase, let alone the market or BTC in general, and why would I leave money with people I have no reason to trust and have no means of penalizing should they fail to honor their terms with me.
The reality, as others point out, is that Coinbase has people dumping real money into their system to get in on BTC, and thats what Coinbase use to pay my withdrawal, which is as simple as I could have imagined it. I just dont know why.
so the fact that BTC is crypto doesnt change anything about how trades happen, but the massive differences in market structure between crypto and established markets makes a huge difference
edit: and the fact that the difference is larger does matter. volatility is one of the core inputs of derivatives pricing, and for a derivatives market to exist, volatility must be estimable. having a derivatives market has major influence on prices and liquidity of the market for the original security. for BTC to really go mainstream, markets need to evolve