The equivalent exists for solid-state storage as well. It is useful in some contexts to characterize the capacity and throughput of the various firmware subsystems in the same way.

Much of the motivation when I learned it was based in characterizing the storage to identify defects and weird or anomalous behavior that were not disclosed by the manufacturer. Oddities are relatively common. At the most basic level this was useful for tuning I/O scheduler behavior. Just as useful, it allowed us to surface storage hardware issues to customers before they blamed our software.

Probing the properties of storage hardware is a cool but rarely written about area of systems software with many ramifications for managing performance.