Our upstream provider of virtual numbers filters out verification codes from services like Google, Facebook, and Twitter.

The advantage of using a physical number is that no messages are filtered out.

They are more expensive because they are more expensive to me. And the typical customer only uses a physical number for one day, where the minimum purchase time for a virtual number is one month, so the effective price to the customer is "only" 4 times as much.

It's better than Twilio because Twilio filter out verification code messages, and because Twilio don't allow anonymous signup or Bitcoin payment.