Thanks for asking -- we've played around with it a bit! Mostly as tests as features get implemented, e.g. live-playing incoming audio, or playing forward through multiple messages at a time, but it's kind of addictive so we've ended up just chatting sometimes too.

Heysync definitely shares concepts with iMessage's audio snippets (or WhatsApp's, Signal's, etc.), but automatic transcriptions let you decide to read or listen at will.

It's also different in that it's got features similar to IRC or a slack-like, so channels and DMs, markdown and code highlighting support, and soon enough reactions, threads, bots, etc. Beyond that, I'm also working on adding built-in support for "structured" meetings, like daily standups, because that seems to be a major use case.