There's another idea too, that docker is essentially a userspace service manager. It makes things like sandboxing, logging, restarting, etc the same everywhere, which makes having that multi-line build script more valuable.
In a sense it's just the "worse is better" solution[0], where instead of applying the good practices (sandboxing, isolation, good packaging conventions, etc) which leads to those benefits, you just wrap everything in a VM/service manager/packaging format which gives it to you anyway. I don't think it's inherently good or bad, although I understand why it leaves a bad taste in people's mouths.
In a sense it's just the "worse is better" solution[0], where instead of applying the good practices (sandboxing, isolation, good packaging conventions, etc) which leads to those benefits, you just wrap everything in a VM/service manager/packaging format which gives it to you anyway. I don't think it's inherently good or bad, although I understand why it leaves a bad taste in people's mouths.
[0]: https://en.wikipedia.org/wiki/Worse_is_better