Give yourself some credit here, I'm a web developer who works on billing systems and I also have no idea what it is that they mean. My best guess is that they're making a marketing message that they do not have a very particularly annoying workflow of a very particular billing integration (Stripe webhooks maybe?).

My problem is when you know that workflow, and that integration... you actually don't need it, its just nice to have. Its just a way for Stripe to send you updates to an endpoint with the status, like if say a card has declined as the charge is closing. But you can just poll.