Don't take me wrong as I'm using Owncloud & Nextcloud myself. Lately I did some test on Seafile in my virtual lab and found out it's extremely fast in terms of synchronization speed. What bothers me is that Seafile splits files into blocks on the server which makes admin job a bit inconvenient at the server side. But that is also the reason it's outperformed Owncloud & Pydio as it does delta sync.
Another advantage is that Seafile still support Windows server. Not that Windows is better than Linux but not a bad thing for users to have another choice.
So my question is , why Owncloud/Nextcloud is more popular here? I see people talk about Seafile on Reddit all the time but never seen it happened here.