This is an arbitrarily chosen key and it's not currently reusable in other important contexts. To use the .compile namespace, you have to duplicate what's in the
:dev key if you're compiling for dev. If you're compiling for a release OR you're using .main in a release environment, you may have some opts you want to load as standard (or not, it depends. Not sure
:profile :prod counts, but if you have a few like
:key it is more useful). If there's more ways of setting the opts, then you may want to choose your own opts for the .dev namespace too, so a model which allows that to work consistently is certainly valuable. .compile is particularly interesting (compared to .main) in that there's no single obvious place for it's opts.
Using a key inside system-config.edn may be the completely wrong approach. If that's the case, then it becomes the holder of only the
:system key, making it seem a little redundant.