The biggest advantage for docker in the "home lab" environment is to be able to try out an app, but if you decide you don't like it, removal is simply deleting the container and the data folder. That's it. No trace left.
Sadly you can't say that for installed apps.
But I agree, if it ain't broke, don't fix it. Seems DietPi will be right up your street and look after things exactly how you want, simply ๐
To counter my own "easy to migrate" argument, DietPi includes a backup utility called 'dietpi-backup' (genius naming convention, I know!) which you can use to backup your whole system to another drive. And of course restore your whole setup on a clean install.
Also very useful for rollbacks if needed. I have a 2.5in 5400rpm 1TB drive attached to my DietPi server which is just for backups - it backs up every night at 2am and it's incremental too. I have 5 days of backups and it's one command and a couple of 'Enters' to get it rolling back to an earlier config - really easy and useful when a recent kernel update broke my ethernet adapter (Debian's fault - not DietPi!).