Why /opt/conda is user writable in docker stacks?

I am looking into installing z2jh and was planning to use docker-stacks images. Looking in the docker files I see that /opt/conda/ is owned by “jovyan” and so packages installed system-wide will end-up there. Now my understanding is that in a default z2jh installation only /home/jovyan would be mapped to some PV and saved between sessions while any updates done to /opt/ filesystem would be lost.
So question: what is the motivation for having /opt/conda user writable? Isn’t it better to have that part read-only so that users do not accidentally loose some work after installing packages system wide?

I believe the idea was that users can still conda install or pip install in the container. Those installations being reset on restart may or may not be a good thing (harder for users to break their environment and prevent server startup, for example), depending on the use case. Building an image to serve all possible use cases just isn’t possible.