The most useful spell.

For example, Hearthstone, which is a popular game right now, is a card game! The outcome largely depends on what cards you are dealt, something that wouldn't even occur in Heroes.

Therefore, this game cannot be considered from a serious competitive point of view, because the point of competition is equal conditions, where skill and ability determine the outcome. If randomness significantly affects the result, then it is more of a gambling game, a fun pastime, but not a serious competition. Yes, tournaments and other events can be held for such games, but it is unlikely that the result will show the strongest player. Rather, it will simply show the luckier one ;)

But this is not about Heroes and our topic; it's just a side note. As for the ATB scale, I don't see anything wrong with it either. I just pointed out that it is less suitable for competition due to that very randomness.