In Microsoft's 70-680 MOAC Lab, there is an assignment to create a disk volume (named Alice3), and mount it in a folder which itself is created inside a separate volume (named Alice2). I'm wondering if this is a common practice , or whether this is just an exercise to show it can be done?

The rationale for doing this sort of thing escapes me. One could just as well make a start-up script that mounts the volume. It wouldn't be the first time Microsoft provided more than one approach to a result. It just isn't clear to me what the trade-off is for taking one approach over another.

Any input here is appreciated.

I think I have found (thunk?) the answer to my own question.

Volumes that are mounted in folders allow different file systems (Fat32, exFat, NTFS, etc) to be accessed as if they were a single file system.

It also acts as a kind of hack to extend the size of the system drive c:\ .

Being even more imaginative, I suppose on could create RAID-5 or RAID-1 volume(s) so as to provide some degree of fault tolerance for data contained in those specific folders.