Even leaving aside that the password is sent to the server when using the web ui, seafile's security leaves a lot to be desired.

For example file names, modification dates, sizes, and other meta data is NOT encrypted. This is a big deal if you sync something like your home folder (things like your browser cache or even Downloads folder may leak a LOT of info).

The defaults on the (self-hosted) server are also very insecure and there's no mention of anything in the installation guide.

It's a shame because Seafile is so much better than things like nextcloud in my experience and there truly is nothing else like it; It really is just as convenient as using google drive!