Msats are indeed real, they can be added on lightning and liquid pretty easily while on the base chain I think it would need a soft fork and for wallet providers and nodes to run the new soft fork software.

We don't really need it now, but as more bitcoin is locked up and lost and deflation around the world continues, even a single sat may not be practical for a transaction and mSats will come into play

Is .01 USD real? Yeah. Can you buy anything with it? No. Pretty much same thing with mSats imo.