I mean sure, you raise an interesting point that at low enough refresh rates application architectures and display protocols begin needing to explicitly account for that fact in order for the system as a whole to make use of the feature.

But the other side of things - the driver and compositor and etc supporting arbitrarily low frequencies - seems like it's already (largely?) solved in the real world. To your responsiveness point, I guess you wouldn't want to use such a scheme without a variable refresh rate. But that seems to be a standard feature in ~all new consumer electronics at this point. Redrawing the entire panel when you could have gotten away with only a small patch is unfortunate but certainly not the end of the world.