No there isn't. I have no idea how they pulled it off, but it really is instant. In less than 5 minutes, I went from not having a Circle account to having a Bitcoin transaction on the blockchain transferring BTC I bought with a credit card to my own private wallet.
The issue with this (as you probably know) has always been the danger of chargebacks.
I ran across a reddit post [1] discussing it. I dunno if they've completely dealt with the issue, but it is pretty fascinating to see they are even trying.
Circle is amazing.