as someone who works in retail and see's consumers use zip...

as someone who works in retail and see's consumers use zip etc... its obvious to me that customers don't really care who they use, they generally have a few in their wallet and will manage between them. some are better for small purchases, some better for large. Its NOTHING like an iphone, where there is a cost barrier to having a samsung, pixel, huawai etc all at the same time. these are service providers with zero cost, so customers will always choose multiple. and where they choose multiple, there will be competitors, albeit some much smaller.
Retailers use it as a chance to to get in front of new customers - they use the BNPL's footprint to get in front of the customers via online advertising etc etc so happy to pay the few percent they pay @ transaction - cheaper than getting someone to watch a tv ad who doesnt buy anything.