Speed factor.

I can add that (although I think I've read something similar somewhere else) that in the early stages of the game, when there are no high-level, fast monsters yet, it is recommended to include enhanced monsters of levels 3-5 in the scouting party (to increase movement on the map) or in the main army (to gain the first turn) – Djinns, Rocs (speed 11), Pegasuses (speed 12), and Dragonflies (speed 13). If the hero's specialty involves these monsters, their speed increases by another 1. If the hero also has 3 artifacts that increase speed, and the battle takes place on their native terrain, then the maximum speed of a Dragonfly (level 3) in battle can reach 19 (!). I think that in terms of speed of construction, cost, and speed, the Dragonfly can be considered the best expendable, fast unit.