This is important, because no alternative to external (HTTP[S]) URI regex manipulation exists, so without this feature, a user cannot restrict intra-package autofill.
This will become more important when the relevant desktop platform-specific schemas are added for desktop autofill, since those situations are usually more security-critical.
Since even https://play.google.com/store/apps/details?id=io.github.ratul.topactivity – a Play Store app – can transparently acquire the current activity in the background, Bitwarden is not fundamentally prevented from doing so too.