If I were YouTube right now, I'd be evaluating the opportunity to eat Twitter's lunch as it'll get distracted by a randomizing new owner. The YouTube posts product really isn't relevant in the current YouTube app, but as a separate experience focused on posts, it might have some value for non-creators on the platform. Bad as it is, YouTube has more of its act together than Twitter when it comes to designing and enforcing content moderation policies at scale.
Today while selecting a handle I was wondering why YT is doing this. There is no real added value except for using a standardized symbol used in social networks.
In my eyes YT is no social network, even though many claim it is.
The comment section, where the discussion and interaction takes place, is like SMS is to WhatsApp, in the sense that it has no surface to enrich dialogue. For example, you can't add images in replies to a comment, comments can't be embedded in websites.
I don't see how they can expand to a multimedia platform, which is what Facebook, Twitter, Instagram are. They're just a video platform and lack everything else which could move it towards a multimedia platform.