Ulysses? Take an app with a MUCH wider audience: WhatsApp!
They use Markdown-esque syntax for message formatting. It mostly is Markdown, with a single caveat that gets me a lot: *Single asterisks* become bold, instead of italic. For italics, you have to use _underscores_.
Other syntax works fine. Slack also uses Markdown. In summary that's nice as it is just one single syntax to remember across systems. I wouldn't enjoy too much that every app started having its own different, more expressive syntax, at least not for apps which their primary job is communication, not text edition.
They use Markdown-esque syntax for message formatting. It mostly is Markdown, with a single caveat that gets me a lot: *Single asterisks* become bold, instead of italic. For italics, you have to use _underscores_.
Other syntax works fine. Slack also uses Markdown. In summary that's nice as it is just one single syntax to remember across systems. I wouldn't enjoy too much that every app started having its own different, more expressive syntax, at least not for apps which their primary job is communication, not text edition.