If we are talking about APIs, there are normal http requests, to access the request includes the token, the response comes in JSON format. And what to do curlом or other means is not important.
If we are talking about parsing, then there really is the opportunity to work with both html and json. For example, any channel type https://www.instagram.com/instagram/
there's a JSON version (unofficial of course) that can be picked up at URL: https://www.instagram.com/instagram/?__a=1
JSON resource to get more profitable because:
1. It is smaller
2. It easier to parse