I don't think any of that means the benchmarks shouldn't be taken seriously. GP didn't say they expect Bcachefs to perform like EXT4/XFS, they said they expected more like Btrfs or ZFS, to which it has more similar features.
On the the configuration stuff, these benchmarks intentionally only ever use the default configuration – they're not interested in the limits of what's possible with the filesystems, just what they do "out of the box", since that's what the overwhelming majority of users will experience.
On the the configuration stuff, these benchmarks intentionally only ever use the default configuration – they're not interested in the limits of what's possible with the filesystems, just what they do "out of the box", since that's what the overwhelming majority of users will experience.