I've never done consumer facing payments so I don't quite understand what are they selling here.

Why not use Paypal directly for example (since that's one of the gateways they support)?

My question might sound silly but in B2B you just use wire transfers. So, I don't see the need to stack up too many layers for payments when each layer wants some money for the service they provide.

Is their main feature the fact you could switch gateways -- ie. they are selling an API wrapper?