The persistence is just 1 factor... LCD response time is very slow compared to OLED (~5ms vs ~0.01ms). Every millisecond is important when it comes to VR.
While you can do that with LCD, you have to wait 5ms for the pixels to change before you can strobe, so your frame is an extra 5ms out of date. That's my understanding at least, I'm not an expert by any means.