The fact it was recommended more, and doesn't require an invite like Tildes. I only heard of any of these because of the migration, and only heard of Kbin here on Lemmy.
I wanted to try Tildes after seeing the page, but I have no friends there to invite me to try it.
Yeah, on deeper reflection, Tildes is a wall garden, which in itself could be an isolating experience. A tight control on its users runs the risk of making it an echo chamber just like majority of what reddit used to be.