Basically, can a third party IDE run inside a Vision Pro device to give programmers the opportunity to live test the API in real world circumstances?
Static programming may be safer and all that is allowed for end-users, but there's a jillion use-cases for live programming using the Smalltalk IDE (e.g. Squeak) undreamt of in the current Apple development ecosystem.
There's always ways around whatever walled garden Apple sets up, but if Apple allows developers the same affordances for testing their apps in vOS by installing them on at least their own vOS device that they do in iOS, then they can't stop it and instead should embrace it.