There is a penalty for hitting air, increased LT stamina drain and a bigger window for a punish.
I talk about it here in my stamina tips video.
https://youtu.be/QR5lfu4bF6Q
Also, here in 18:00 Martial talks about the bug where your block overcommits and you can't move your head, as I was talking about earlier.
https://youtu.be/VGvAmkXqQ5k
Also, I don't think I've ever seen anybody use triple Uppercuts effectively in higher divisions, unless it's from the mighty Saki