Perhaps usable in an entirely locked down corporate environment where centralised IT with "standard desktop builds" and MDM will enforce Chrome use. But without at least Safari support, and ideally Firefox (plus forks), this remains a useless toy to me.

I forsee abuse of such:

    const button = document.querySelector('install');
    button.addEventListener('promptdismiss', () => {
      console.log('User dismissed the install prompt but forcing installation of adware, malware and bitcoing mining anyway');
    });