Speed over silence, basically. At 7,200 rpm it's quicker than the 5,400 rpm crowd, and it'll suit a small box that lives out of earshot. It's CMR, which is what you want anywhere near a RAID or ZFS rebuild.
!Watch out for
Treat that bay rating as a hard limit. Anything larger wants a pro or data-centre drive. Warranty's three years and the workload rating is 180 TB a year. At 18 TB that's 10 full passes of the drive a year, and a monthly scrub uses twelve of them before you've written anything.
Backblaze doesn't run enough of these for a failure rate we'd publish. Power draw is 4.16 W idle and 7.41 W working on Toshiba's figures, or 36 kWh a year if it spends the whole year idling. A 4-bay box full of these gives 54 TB after one drive's worth of parity.
Specifications
Each value links to the Toshiba page or datasheet it came from.