You pretty much have to buffer a couple frames because that's how rendering works. You can do work to reduce extras, but it only gets you so far. And screens tend to want to buffer at least a frame too, and it's hard to convince them not to.

You also need quite high framerates to make rendered motion come out reasonably smooth. Especially for something you're trying to follow across the screen with your eye. Fake motion blur only partially helps and has its own problems.

I wonder if it makes sense to render at 120hz internally but skip every other frame? That should have a similar improvement on latency as actual 120hz.

I agree that following things across the screen is a use case for higher rendering rates.

That helps, as does triple buffering at very high framerates, and various techniques to try to align rendering exactly with when a frame is needed.

But it's still significantly better if you put that 120+Hz output onto a 120+Hz screen, and it's not super hard to make them.