Well you're in self-hosting so if you don't know docker yet, you'll get the advantage of learning it. It will open up many self hosting opportunities.

For me one advantage is just one central place for all my containers. I don't know how the package center handles storage but the docker version you'd have clear and easy access to the storage mount and would be able to make backups before big migrations, and you could set it up on a new server in the future. Imo there's just no reason to use the package center one unless youre not very tech savvy and don't want to learn anything else related to self hosting. I'm just assuming package center is easier in that regard but again i haven't used it.

Also, when there are critical CVEs like the nextjs one found this past week allowing RCE then yeah, you want your stuff as up to date as possible. You don't want to have to wait an unknown number of days for a downstream version to get updated. Docker let's you get your updates straight from the source