It's not just SSB. There are entire classes of games that aren't playable even at novice levels on modern LEDs like Guitar Hero style rhythm games.
LEDs often have much higher latency than necessary. Many have ALLM modes which disable certain features to decrease latency. We already have changed LED technology for this reason -- higher end computer monitors specifically focus on latency now. It's a really big deal.
LCDs may refresh pixels at a rate of 1ms, that does not mean the pixel displayed is only 1ms away from the input. You can get maybe 10ms of input lag with the very best setups. Modern TVs easily have 100ms of lag out of the box due to processing which you may or may not be able to bypass.
LEDs often have much higher latency than necessary. Many have ALLM modes which disable certain features to decrease latency. We already have changed LED technology for this reason -- higher end computer monitors specifically focus on latency now. It's a really big deal.