I prefer not to mix my development files (plugins / themes) within the wp-content folder. Inevitably when copying wp-content from production - I will wipe out my local files (oops)
I prefer to symlink from within the container to a separate /volume for the files I am currently editing. Then if I later re-copy wp-content (as above) - then I merely have to re-create the symlinks.
This would also be useful those who use build tools such as Composer, Gulp, npm et al - i.e. building would occur outside the container - and we don’t load down the container with those tools.
e.g. on my mac - I could select a folder such as ~/projects/plugins to mount as “dev” - then in the container - I could symlink to /mnt/dev/my-plugin in the plugins directory - voilà!