Totally agree that we have way more time for the 45 round tournament. We can do it slowly and eventually still complete the tournament.
However, this is a probability game. In theory, we have better chance to win using higher level/rarity animals so we should try these fighters first. The question is at what point, if nothing works out, we should start trying Common Epic animals like Pyro Pony. As we all know, these common animals can still win but the basics of the game tell us that the probability is just lower. We have a lower expectation for these common animals to win. Thus, when they do win, sometimes we exaggerate their power/success rate.