@lzg IMHO, chat is not really async because of societal conventions. With chat not being async, it's true that chat is not the best way to discuss complex issues.

Email is.

However, I joined my first company that did not use email in 2019, so somewhere before that we decided to kill the best tool we had to discuss complex issues.

Since then, we've been searching for reinventing email. (Zulip came a bit close!)