The absolute minimum amount of knowledge needed for this sort of thing is how to get files onto a server. Lots of people capable of that have absolutely no idea what Docker is or how it works. Lots of people know what it is, and what it does, but have not ever actually used it (like me!). If I was going to install some server software, and saw Docker, it would put me off — great, I have to learn Docker now?

Docker probably is a better way of doing things, but it’s another layer.