There is an option to transfer USD into your actual USD wallet on coinbase. If you do this it will still take the time it did for bitcoin, but you wont lose the money. Once funds are in this USD wallet you can then buy BTC instantly on Coinbase. This would prevent fluctuation while wating.
Hope this helps.
They never gave me the usd wallet option on there, and I know exactly what you're talking about. Not sure why that isn't there. All I have is the vault and the coinbase btc wallet
