Is it necessary to use docker in this circumstance?

Just 1 or 2 PHP/Python project hosted on a single server.
Using redis for cache, postgresql for backend db and nginx as web server.
What’s the advantage of using docker?

mmm, perhaps might help

I use Docker to speed up development and testing. By using a Dockerfile to build and run my projects, I can be sure that I have exactly the right pre-requisites, and a very repeatable environment.

I can also run multiple senarios at the same time, as all the containers are isolated unless I link them.