You probably mean "you need docker to self host it".

The only way to guarantee consistent behavior of software across different devices is if they all share the same base environment. If this can be achieved by any other means great.

It is one of the solutions to "it works on my computer problem". Most home server solutions (start9,umbrel etc) are built around this.

Doesn't matter if it is well designed if it can only run on the Creator's system.