Docker containers usually have a negligible performance overhead compared to bare metal. Certainly it won’t make or break jellyfin usability whether it is running in a container or not.

Some further advantages in addition to the ones you mentioned:

• trivially easy to up and downgrade versions (in case of a broken release for example)
• nearly 0 chance of incompatibilities stemming from your other installed packages or versions
• If your server is open to the public internet and you get hacked due to a flaw in jellyfin, any attacker finds himself inside the container. One typically mounts all media as read only into the container - so at that point all they can do is mess with your playback history and steal your home videos but a ransomware attack against your actual data is off the table.

edit: obviously you should still practice good security practices like requiring HTTPS, geoblocking etc. if you are open to the internet. Luckily there’s a fantastic container which pairs perfectly with the (imho preferrable) linuxserver/jellyfin container which provides this: linuxserver/swag. Just FYI