Behaviour
Donkeys have a notorious reputation for stubbornness, but this has been attributed to a much stronger sense of self-preservation than exhibited by horses.[24] Likely based on a stronger prey instinct and a weaker connection with humans, it is considerably more difficult to force or frighten a donkey into doing something it perceives to be dangerous for whatever reason. Once a person has earned their confidence they can be willing and companionable partners and very dependable in work.[25]

Although formal studies of their behaviour and cognition are rather limited, donkeys appear to be quite intelligent, cautious, friendly, playful, and eager to learn.[26]"

-Wikipedia

Donkeys are far from being useless.