The tendency is for people to invoke features situationally. If you are communicating with someone who is using rich-replies there is a tendency to also invoke that feature yourself. If people are using emojicons there is a tendency for others to play along rather than use plaintext characters. Feature invocation is situational and relative.

> Two services don't need to have identical feature sets to interoperate, because you don't need perfect, full interoperability, if you can send most of your messages across platforms, that's still pretty good.

This has proven to result in an unacceptable user experience throughout the history of messaging. When a system loses social information from the environment it is no longer an effective communication tool. Worse, it is dangerous. If you send me a message and I respond to your message with some thumbs-up emoji, and your platform doesn't support it (e.g. a text-based IRC client) that information gets lost. You believe I have disregarded your message. You may assume I have been rude when the opposite is true. This is absolutely unacceptable UX.