Hard disagree back. Email has multiple contexts when I would say that short form is ideal and should be the default but at times a thoroughly long form email is needed. Or, honestly, you just need to create a document at this point. It could be a slide deck or word/markdown/excel/etc (depends on context) and this should be in the email. But email is key.

My experience is that people search subject lines, conversations, dates, and generally traverse historical conversations much better in email than in chat or a fully external application. They won’t search Slack, or try but can’t find the conversation. They won’t remember it’s on a wiki, you’ll constantly be redirecting them to the url. If the file is attached to an email, sometimes they’ll resurface it from a year+ ago. I find that’s way more common than someone referring to a chat from even a month ago. Chats are semi ephemeral. I’ve used both Teams and Slack and feel neither has really changed the game in terms of how the entire user base of an org use the system, enabling the historical reference points and moving it out of a ephemeral state, so email remains a stalwart for archival purposes and helps provide maximum context after the fact (people tend to elaborate on their choices more when writing an email).