These kind of streaming apps are app stores themselves. They are a window to another world that is not controlled by Apple. Apple is likely worried that it may

These kind of streaming apps are app stores themselves. They are a window to another world that is not controlled by Apple. Apple is likely worried that it may not stop at streaming games. Why not stream other apps as well. Usability will be fine if you come up with clever ”codecs” to encode transmission of UI. It’s true that Safari already enables this, but it has its limitations and Apple is controlling what can be done there.