The source clarifies that this only applies to websites run within the Safari browser.[1] PWAs added to the home screen aren't affected. > As mentioned, the seven-day cap on script-writable storage is gated on "after seven days of Safari use without user interaction on the site." That is the case in Safari. Web applications added to the home screen are not part of Safari and thus have their own counter of days of use…
As the article has been updated to say, "installing" a PWA to the home screen is an optional step that many people prefer not to do in favor of bookmarks or the address bar or the new tab page or whatever. But it's no surprise that Apple would want to impose an "install" step on the web to prevent it from looking more attractive than the App Store.
The FUD here is getting out of control. "PWAs", that Google pioneered, are all about having an ‘install step’ to put the "web apps" on your home screen. https://web.dev/customize-install/