One reason is if you need to launch a subprocess with a timeout but don't want to use up CPU in the python script while that subprocess runs. The regular subpro

One reason is if you need to launch a subprocess with a timeout but don't want to use up CPU in the python script while that subprocess runs. The regular subprocess module will busy-loop in such cases, consuming CPU, while asyncio's does not. The docs even warn about this for subprocess and suggest using asyncio to avoid it, although the docs are misleading - it only busy-loops if the timeout is not None, and only when running on Mac/Linux not Windows.