I have never liked Coinbase and with freaking out, I guess they are investigating it. Being an utterly centralized system, they are working on bringing something new to the Bitcoin/crypto community. Hated them when no Segwit, realized large scale operations takes time for implementation. They are yet to implement batching, but they are rolling it out.
Isn't BTC to USD volume one of the top, and isn't it Coinbase/Gemini one of the major exchanges, guess they have got no reason to compromise their credibility, too legit for that.
Would be vouching for a decentralized exchange, but for the time being it ain't really practicable, not convenient.
I guess they are a bit slow, but do respond.
PS: 13 million users, 900 negative reviews on a not trustworthy reviewing trust pilot, what to say?
PSS: Not a US citizen.
https://techcrunch.com/2018/02/16/visa-coinbase-not-at-fault/