Because it's harder to set the content-type from browsers.
Perhaps if your API won't be that useful to browser based clients, perhaps that'd be the way to go.
Perhaps if your API won't be that useful to browser based clients, perhaps that'd be the way to go.
That's only when using HTML forms or links, TFA does not even mention the option of multiple representation of resources so it's irrelevant: there's nothing hard to adding an Accept header to an XHR.