Perhaps I should have added, the largest barrier to JWS seems to be
the poor understanding of programmers as to the many benefits it brings.

That and the learning curve for JWS deployment.
( Rolling your own key certificate can be tricky, and is
quite daunting the first time you approach it, whereas buying
a certificate is expensive. )

It can do that, but depending on how you package the app and how you
configure the JWS server, it can be a lot more clever.

Cheers
    Bent D