volgens Dimitrios Desyllas.
Well docker is Not a casual user tool is mostly a developer/sysadmin tools and a way to serve/provide applications and needs a bit of skills.
But more "advanced" fellows or professionals need some tools too right?
So anyone has the freedom to choose either docker or native way in order to have a manual web-based moodle installation either way is fine. In the first place is desighned to fit the needs of a specific organization as you can see and I offer some encahncements.
Also look it as that the docker way is a good/easy way for IT professionals to offer you (to people without technical expertize generally) a quick moodle installation and not even bother. On a problem you just tell her/him that it does not work and he/she fixes it ;)
Also to answer your question why to bother to make a docker image is that docker offers you an isolation and security layer so if a blackhat/greyhat hacker hacks your app he cannot mess around with the other apps or even with the whole server and another running sites. Also if your server has a problem you can move your moodle installation it easily (because you are moving a whole system and not just an app) into another machine and work just fine.
Also many platforms such as azure offers you docker technology to run an application so you do not bother with server stuff to much (I guess) you just do whaterver to run in to your pc and then launch.