I guess when you buy pizza?
edit: wait, is this where I'm supposed to have an epiphany that I never have to pay over the phone?
Well when I order food, I call and place the order and hang up. Once the delivery guy is here he gets his 3G card reader and I use Paypass to tap the CreditCard and I'm done...
It's the same with convenience store, I place the call they bring the machine and we're done. I can't remember the last time I used my card over the phone.
Anyway, to each their way.