so why not just use a jellyfin client?
Depending on what you are playing and what setup you have, the Android players are just not good enough.
With the default web player, you lack audio passthrough and have to transcode most subtitles, with ExoPlayer you lack many codecs in passthrough, when using an external player like VLC you lack proper progress tracking.
Kodi/CoreELEC does it all: plays most video codecs, passes through every audio codec in existence, automatically switches resolutions and refresh rate, has no issues with high bitrate 4k, switches HDR on the fly and syncs watch progress to Jellyfin.
The Kodi sync plugin is essential though.
So that is the reason? I had to manually rescan my entire music library ever since 10.9 released.