A geolocation API can be used to conditionally present content based on the user’s location. A payment API can be used to conditionally present content based on whether the user has paid for it or not.
Look, I don’t necessarily believe that HTML5 should have a payment API, though I do think that the open web should support getting paid in a way that bind people to a single company. My argument is that declarations like “a payment API is fundamentally inappropriate to HTML” reflect an ideology, a belief about the way the web should work, rather than an essential truth about the way the web can work. At one time a lot of people would have argued that “a geolocation API is fundamentally inappropriate to HTML” based on a belief that cyberspace should transcend physical location. Clearly that belief is no longer very popular in the face of the money to be made with location-based advertising.
Note that I’m not trying to cast aspersions on ideology. I don’t think a non-ideological, “purely technical” stance on the web is possible. You can’t design the web without some set of beliefs about how the web should work. But we should try to avoid claiming that those beliefs are determined by the technology and thus not up for debate.