In the event they abandon again, they're leaving even more users vulnerable. The only thing CalyxOS has over AOSP is the removal of the Google Play Store... in exchange for microG, which runs with elevated permissions as well. Ignoring that, as I said in my comment above the one you're replying to, a third of the supported devices are GrapheneOS compatible. The other two thirds are covered by LineageOS, which imo is just as secure as CalyxOS (probably even more secure than Calyx given they abandoned their community for about 10 months).