FYI
After Sept. 18, you’ll no longer be able to send or receive direct messages on YouTube as we focus our efforts on public convo tools (comments, posts, etc).
You can still share what you’re watching w/ others via the Share icon below videos.
More→ https://yt.be/help/9Hns
I use it occasionally to talk in group chats with other channels about our content. Sometimes there are things you want to disclose privately to a close friend content wise.