Take the chat logs from any organization, no matter how perfectly rule-abiding, pure and saintly and a prosecutor or adversarial lawyer will be able to find snippets of text that can be taken out of context to make them look bad.
Chats, emails, zoom calls, in-person conversations, etc all make sense to be ephemeral. Official company documents published by HR, official specifications, advertisements, etc make sense to be kept long-term.