Hum, I think the default version of python on the mac is 2.7, but I'm not sure. And yes, there is pyenv to help. But if you want someone outside the python world to use your project, pyenv is not very friendly. It is more friendly to use "apt install" or "dnf install", so being able to generate an executable is a good option :)

I don't know DLL to talk about it ^^

And Docker is definitely a great option, I use it regularly.

Not everyone likes web/GUI solutions. Being able to package a Python program as an executable is just another trick up your sleeve :)