That's fine in theory, except that some very common Windows Objects can't be serialized in any meaningful way (most painful one for me being the Windows Update Client), which means that certain "remote" operations are actually affecting the client machine, or are failing because the client lacks support for certain operations.
I've been using Powershell since v2, but to me, it's essentially a walled garden automation environment. Just one more way for Microsoft not to give you the tools to efficiently manage your fleet.
a) I think the normal use is something like SCCM or InTune to automate Windows Updates, not manually connecting to a machine and trying to script the Windows Update Client.
b) Microsoft built Azure Stack with PowerShell automation. Are you saying Microsoft refused to give themselves the tools to efficiently manage their own fleet? What tools even are these?
That’s why I can guarantee Remote Desktop has more usage than these remote rpc calls for ad-hoc work. Powershell is quite powerful but it’s features are more for programmers than users.
Because of its complexity RPC is not a replacement for ssh where you are typing commands directly to the remote machine.
Passing serialised scriptblocks to the remote host, executing them, and getting serialized objects back. Meaning you can pass serialisable objects around, handle errors, the multiple output streams, etc. over the remoting connection.
Because it's integrated into the language, you can pull PowerShell modules over from the remote host to the local host automatically generating proxy stubs for them ("implicit remoting"). E.g. to manage and Exchange server you can remote to it, and bring the Exchange cmdlets back, and then import them locally as if they were a local module.
It's also able to do that and edit the proxies as it builds them for you, to allow and restrict what commands you get - based on your permissions and perhaps which tier of service you're paying for. And not just allow or restrict commands, but allow or restrict individual parameters on those commands, if desired.