It actually does, but the virtual disk that StableBit DrivePool spawns does not service any pool I/O. All pooling is done on the filesystem level before reaching the virtual disk. Think of it this way, all I/O targeted at the pool is redirected at the pool part drives before reaching our virtual disk.
The virtual disk itself is a proper block-based device, and you can read from it, but you will find that it's simply an empty GPT drive.
For StableBit CloudDrive, where we store the actual on-disk data, the emulated disk will show proper performance statistics when working with data on the volume.