Certainly if you don't see any value in this, westor, him, sees the value.
In it's simplest form, the value would be the same as knowing the size of the disk. It could be used for display purpose, like general stats about disks.
As far as more elaborated scenarios are concerned, it is explained in a stackoverflow link (unsure if it's the one posted here) that they wanted to know if it's an SSD, to eventually load objects in a map in a different way, I think it's a valid point, you are loading the objects from files on the disk and perhaps you want to load them all if it's SSD, or load them 'later' if it's not.
Not the best feature we need, but not the worst, if tomorrow there is a reliable way to know if a disk is SSD or not, it would simply improve $disk imo.
