I think this is a good idea. Developers should not be able to store something on my computer indefinitely without my consent. This doesn't apply to applications users add to their home screen.

This doesn't "destroy" the PWA ecosystem. Just makes a user's intention explicit when they save a PWA to their home screen, rather than continuing to use it within the browser.

From the WebKit Blog (https://webkit.org/blog/10218/full-third-party-cookie-blocki...) "Web applications added to the home screen are not part of Safari and thus have their own counter of days of use."