If there are no truly useless monsters, then there are only bad tactics. I am completely unable to play with:
- wolves (Nature), even though they attack twice, their speed is very low, and their mortality rate is high. Fairies look much more preferable due to their retaliation ability. I try not to buy them at all. I don't want to waste money.
- ballistas (Humans). They are so slow that they cause more harm than good; I don't see any point in buying them, except for defending the castle. For me, an army must be mobile.
- orcs. They are expensive, slow, and ultimately ineffective. Especially when there is such an alternative in the form of cyclops.
Maybe I'm a bad tactician, maybe I'm greedy and stingy, but these units are a rare sight in my army.
I agree with you. They are useless, but only not at the beginning of the game. I personally like to play with one hero, and it doesn't matter if he is a mage or a warrior. It's just more convenient and easier for me. But at the beginning of the game, I wouldn't refuse any of the units you listed. You need to level up first, and then go on a journey with creatures that will help you. It's convenient to play with creatures in your army when you know who your opponent is, and then it will become clear whether you are a good tactician or not.