A prebuilt Codespace is basically a template consisting of ...
... a huge external dependency?
BTW, AppImage exists, so does Docker, so does a lot of other VM like things.
I'm not sure how you can spend your time better than setting up your developing environment to know exactly how things are working, but that could just be me. Also, this isn't a very hard or repetitious process so... (it's kind of like putting batteries in your mouse/keyboard).