That transaction volumes decreased on the /first/ day 3-D secure (and now, the one-time password) was implemented is hardly surprising, but I think once customers get used to it it would have returned back to normal.
I have not been able to use my credit card even once since this was introduced due to various reasons - the SMS service that banks are supposed to deliver One-Time-Password is not sent promptly or I do not have a way to get password to authorize even an IVR transaction in time.
It might all work out after initial issues are resolved but so far I find this to be a pain.
Of course, this does defeat the purpose of an IVR transaction :)
For what it's worth, I'm optimistic: the banks might listen to customer complaints and actually do something about it. I admit that I have no idea what they could do: AFAIK there's no way a telco could even guarantee that a SMS is delivered immediately after it is sent