Being in the IT business for a few decades, email is superior to anything else for record keeping. Especially with Thunderbird I find it almost too easy to find information I need, and addendums neatly threaded.

And, it is quite difficult for the other part to hide/delete stupidness they send, which thankfully saved my behind twice.

Chats are good for now-communication, but energy- and time consuming when you need to look up something that happened months ago.