PS4 Remote Play for PC/Mac being worked on by Sony

[piopakk]

What does this feature actually do? Does it let me play PS4 games through my pc (screen)?
But it still needs a PS4 to be switched on, and using the PS4 controller.

If so, what's the usecase for this feature?? Why just not play on the PS4 itself?

I don't see the value in the feature.