(I'm not saying this is a good thing but ...) Containers are often used where you want to run several programs, but each depends on a mutually incompatible set of libraries. Two programs need python-somelib-1.0 and python-somelib-2.5, but both versions can't be installed at the same time. Or you need to upgrade the programs at different times and during the upgrade window they'd depend on different versions of python-somelib.
Now of course the correct way to solve this would be (a) to make both programs use the same version of python-somelib, (b) make upgrades happen atomically, (c) for Python modules to actually have some API backwards compatibility. But in the absence of doing the right thing you can use a container to effectively static-link everything instead. And worry about the security/bloat/management another time.
Now of course the correct way to solve this would be (a) to make both programs use the same version of python-somelib, (b) make upgrades happen atomically, (c) for Python modules to actually have some API backwards compatibility. But in the absence of doing the right thing you can use a container to effectively static-link everything instead. And worry about the security/bloat/management another time.