Difficult to tell. I'd probably stay within a plain dev environment as long as possible. Just keep in mind you can't rely on host auth within Docker if you ever wanted to use it. Besides, it's never wrong to learn something new, and Docker isn't difficult to pickup.

Often times you want to run a newer version of a package but it has new dependency requirements that conflict with other packages. Most solutions around this involve tweaking the package, or using a chroot. A container lets you avoid this problem as each container has it's own rootfs and can be a different OS and can run different versions of software however you want without worrying about conflicts.

It's somewhat similar to static linking, but at a higher level.