No, just whether or not you'd implement Alipay into your API in a manner that would allow for us to handle the frontend UI ourselves (letting our users chose between Alipay or credit card).
We felt that Checkout was the best integration point because it let us do some nice dynamic authentication logic instead of Alipay's usual redirect-based flow. Given that subtleties involved, Alipay's constraints, and the fact that it'll no doubt need to evolve in the future (as compared to the static standardization of credit cards), I think it'd be pretty tough to expose it via a straight API.
That makes sense. Given the fact Checkout simply returns a token, I think it's safe to say that it can still work with existing backend API solutions in conjunction with webhooks.