The most useful spell.

Because if you remove the ATB scale, it will become completely unclear who goes after whom.

Well, actually, it will.
There is an element of randomness, especially when the initiative is equal, but even with equal initiative, chaos happens in any turn-based game. That is, either there is randomness, or (as I remember) the turn order depends on the position at the beginning of the battle relative to the top/bottom.
In any case, neither of these scenarios harms esports. For example, Hearthstone, which is a popular game right now, is a card game! The result largely depends on what cards you are dealt, heroes don't even dream of such randomness. And there are also a couple of cards with a completely random effect that can easily change the outcome of the match. And nothing...