I was able to transfer funds from my Chase account to buy 10 BTC pretty much within 10 minutes of signing up. However, I did have to verify like crazy - mobile phone, allow direct bank account login, verify address, and populate my coinbase profile as best as possible. Also, the funds transfer is NOT instant. I bought 10 BTC for $699 each a few days ago and I'm waiting for the BTC to show up, which coinbase says will happen on Friday. Since my buy order, BTC is now up to $900-1000 USD today. whoo hoo!
the ACH payment needs to clear, at least to the point where it can't be reversible. that's due to a unique feature of bitcoin being non-reversible. iif coinbase were to send you the money right away, they would stand to risk losing a lot of their money.
Yeah, I like to focus on the part where it returns power to the consumer. But it does have its draw backs. Can't say I wouldn't do what coinbase is doing now in this regard.