I'm not quite sure what is really the advantage of this approach. Docker is essentially a process isolation tool, and is well suited for scenarios when you need

I'm not quite sure what is really the advantage of this approach. Docker is essentially a process isolation tool, and is well suited for scenarios when you need to isolate a running process, but less when you need to isolate an environment. If you need to isolate a part of the file system, e.g. if your environment only concerns Python files, the standard virtualenv (or venv) is perfectly powerful; if you need to isolate other parts of the system, such as memory, installed binaries and the such, your best bet is vagrant (combined with something like VirtualBox). And both of them work fine with a local IDE. Docker works best for deployment, when you want to set up a running process in a consistent manner, and its closed-box approach works really well in that scenario. But in development you generally want more flexibility.