Comment by Haemm0r

It is not only about Google. Its also about the App developers. Nothing prevents them to use the non-google attestation, however they decide not to use it (for many reasons). First time you actually notice this is when you installed GrapheneOS (attestation OK and bootloader locker) and some apps complain about a modified/rooted/... device. Another thing is, that you are warned by your Google device while booting that something is "not OK".