Per my post here, MSIX packages need to be able to pass command line arguments to executed apps. This is presently not possible. Without this capability, my ability to package legacy apps with MS...
Not sure; perhaps John knows.
Certainly there are likely differences depending on how you do it. Two obvious choices:
- Have PsfLauncher run the URL protocol reference. In other words "run the URL and use whatever protocol association is set for http(s)",
- Have PsfLauncher run a browser exe as the target with the url being a command line argument to it. I'd tend to try the latter when repackaging in a corporate environment because browser choice is often dictated, but if a developer is creating this package for many customers, the URL method is probably better.
There is a possibility that the ultimate browser will start outside of the container which is probably not desirable; the result could depend on your choice above. So you'll have to test it. But keep in mind that what version of the PSF and what version of the OS Runtime you test on might change the inside/outside effect. (Which is where I'm hoping jvintzel might be able to shed some light).
The downside in specifying the browser exe to use in the json config directly is that you are enforcing that browser to be used. While Microsoft might feel Edge is the only answer here, the end-user might not agree with that mandate 
.