Yes it does, but if you are building something that works perfectly only using websockets (e.g. a command-line utility), why would you use engine.io? You can t

Yes it does, but if you are building something that works perfectly only using websockets (e.g. a command-line utility), why would you use engine.io? You can tell engine.io to only use websockets, but what's the point if you can use websockets directly and have the same API?