We are using this and it's brilliant. The only thing missing (which I'm told is coming) is a user-definable Thank-You url. Without it we can't finish our goal funnel tracking.
But the integration is crazy simple - took us 1 minute to get set up.
Speed of setup is certainly nice and makes for an excellent demo but over time is almost totally irrelevant. As you note, far more important for a service to actually solve customer needs. If it had taken a half hour, a day or a week to set up but delivered increased sales, it would be much more compelling.
Doubly so for this bank transfer-based service which is already quite slow compared to credit card based services.