Those commands are incredibly unlikely to have anything to do with the DirectStorage API that you are thinking of.
They appear to be a reference to the "Storage Spaces Direct" concept:
An overview of Storage Spaces Direct, a feature of Windows Server and Azure Stack HCI that enables you to cluster servers with internal storage into a software-defined storage solution.
docs.microsoft.com
Has to do with mounting volumes; find here the object under that namespace for VIrtualDisk:
This Management Pack contains rules to monitor Storage Spaces Direct objects.
systemcenter.wiki
So "Add/Get/Remove-VMDirectVirtualDisk" is likely just a shorthand reference for operations on:
Microsoft.Windows.Server.10.0.Storage.StorageSpacesDirect.Discovery.VirtualDisk
Discovery of Storage Spaces Direct Virtual Disk objects.
systemcenter.wiki
You guys are barking up a weird ass tree here...
The DirectStorage API is about efficiency.. not encrpytion.. and BitLocker is way overkill for protecting against piracy, and nobody is going to only release games on systems that are fully encrypted.. no offense, but just total nonsense.