Perhaps. One of the things I sort of like about Twilio is that they can do "credits" and I have the option to only pay for a certain amount.

For me to evaluate something, the amount I'll be billed must have an upper bound that I control. So yes, more solid payment expectations.

Same ^

I really need to guarantee controlling unbounded costs. I would think most people have similar expectations.

Because I'd hate for a bug in my code to result in an accidental infinite loop at 2 AM and then wake up to a $1,000 bill. I'd rather pre-pay and have my task get killed if I run out of credit.

In Germany almost no one owns a normal credit card.

How do you usually purchase things online?

Direct debit, invoice + debit transfer, PayPal are all fairly common options in Germany (+ a bunch of smaller services, + the option of handing the payment to the delivery person, but that's fairly expensive, so I assume it's not used all that often despite being often available)