those benefits rely on the Pixel’s hardware
Doesn't GrapheneOS have a lot of benefits besides the 3 pixel-requiring hardening features which are removed in Graphite (and the 3 others which are disabled by default but can be re-enabled on some devices)?
I'm not disputing that those hardening features are worthwhile! Pixels with Graphene are obviously much more difficult to exploit than phones without those features.
But there are billions of non-Pixel phones in the world which aren't about to be thrown away, and the vast majority of phone users absolutely cannot afford a Pixel. GraphiteOS (if it actually works?) seems to me like it is probably a major improvement over the other options available for them.