point 1: canned animation ; in mkx they use a dial a combo system that has a tendency towards groups of 3, not all the time but most of the time a person is going to decide on a combo as he is inputting it, especially faster ones, liu's 113 for example, the liu player is looking for the move at the end of the string. Not all characters do this but alot will, 11x combos generally.
point 2: 3% health, enemy at 60, 3 bars, time to yolo mofo. in mkx literally everything has chip, if you have the read you might as well do it, while kotal does damage >5% v <60% is straight up true master territory, you would need at least3 solid reads anyway it would be beter to go all in do the combo. Landing the parrys is the hard part, 3 parries and almost any bnb will kill. or better yet 1 straight parry and 2 ex with one ex aagrab in the combo or ex disk. Plus if they are going for the combo, honestly if I were them and someone parried the first two moves in my string, i would extend the string as far as I could, because the buff only lasts a couple seconds and they are limited to at max 4-5 counters. Say Im playing liu, I throw out 113 vkotal, he successfully parries with all three bars, i would immediately throw an ex special at the end, why? unlikely to be parried, most likely has armor, on hit causes knockdown. Say i dont have meter, i throw out dragon roar (backfist special) if he reads that and d1 for the interrupt, im boned, if he was trying to punish and roar connects, he is at 3/4 screen, hard knockdown, and he wont be able to get back in fast enough to justify the bar and the buff will run out.
Point 3: we would do it for the same reason anyone plays fighting games, and low/mid tiers, for the hype.