(Meta note: the commenting guidelines aren't showing up on mobile - it just says "habryka's commenting guidelines".)
Possible benefits (or attractions) of Twitter:
Shooting in the dark:
Longer notes:
The best way to handle content of mixed length isn't clear - by length (and quality). Some short form content here seems like posts, with the downsides of not being able to view it as a post, and less engagement.
Rather than discussions taking place in places, it's based around someone making a comment (in the set of all their comments sorted by time) and someone responding. The format is very different - if I want to read EY's Twitter posts/similar stuff, I know where to go. Celebrities might be there for the less serious entertainment, or because it's where everybody is, or for a lot of different reasons all of which are also there or conveniently linked to.
If intellectual engagement requires focus, mixing it with stuff that requires less focus might make it easier for people to engage, or enable different levels of engagement.
If you want to explore the community more, I recommend reading the Library, checking recent Curated posts, seeing if there are any meetups in your area, and checking out the Getting Started section of the LessWrong FAQ.
The Open Thread sequence is here.