The main issue was (I guess still is), iOS does not allow JIT compilation - in order to keep control over the apps available (having JIT would allow running any

The main issue was (I guess still is), iOS does not allow JIT compilation - in order to keep control over the apps available (having JIT would allow running any code effectively). Of course, nowadays the assets of apps have to be part of the deployable, itself. So it's common to run localhost web server.