How safe and secure is it to do this over the phone?
i also use a prepaid credit card. makes me feel better. and i cant go crazy buying apps, because i only have $20 to get on apps at any time
got eris: 12/24/09
returned eris: 12/28/09
got droid: 12/31/09
rooted droid: sometime in january (right after it was released (manually))
bb->2.1 sbf->desire rom> 2.1bb> 2.2
got incredible as warranty replacement 8/31/10
shattered inc screen 9/25/10-> got insurace replacement 10/4/10
broke inc screen 10/19/10-> got warranty replacement 10/22/10
got moto droid 1 off ebay 1/7/11
broke inc screen 5/26/11-> got insurance replacement inc2 5/27/11
sold inc2 & bought vzw 16gb iphone 4 6/9/11
I don't think it's any more risky than using any other automated service with your phone. I mean, if your bank allows you to check your accounts using your phone, then it's essentially the same thing. It's actually worse, since your bank probably would require you to input your account number and your PIN, which google doesn't need.
I don't think it's too much of a risk, but ya know, using a prepaid CC might not be a bad idea. The only problem is that I'd probably reload it using my phone, if I it was an option.
I trust it 100% because as stated before it goes directly to google. However, no one's information is 100% safe but if a hacker wanted your information I don't think there's much in the way we can do to stop them.