Its much faster to connect, plays everywhere at anytime, its layout doesn't have bullshit and gets right to the point so I can click and start watching right away. No additional crap I have to filter out, no stupid suggestions, and I like the info pages more.
For the rare times I am using a mobile client (like a tablet) I can do normal things like using swipe up and down for bright and volume and speed ahead and back.
I always choose jellyfin first.
For what it's worth: plexpass holder for over a decade.