Rocksdb / myrocks is heavily used by Meta at extremely massive scale. For sake of comparison, what's the largest real-world production deployment of bcachefs?
Production adoption at scale is always relevant as a measure of stability, as well as a reflection of whether a solution is applicable to general-purpose workloads.
There's more to the story than just raw performance anyway; for example Meta's migration to MyRocks was motivated by superior compression compared to other alternatives.