actually, you kind of can
you know, vsync is very bad in terms of input lag for a reason, you practically force the games to wait for an entire duration of buffer so that it can sync perfectly. in reality, even at a 60 fps lock, games will have variable framerate, at microsecond intervals, they will go up and down between 59.8-60.2 FPS. so to sync it, devs usually use heavy input lag inducing vsyncs with extra buffer that forces the game to sync with the screen
with VRR, you can cap the game to 60 fps, but eliminate the vsync. so when the game go up and down between 59.8 and 60.2, your variable screen can do so too, practically achieving V-sync like function without the dreaded vsync input lag. that's what he practically means