I think it is pretty intuitive actually.
The reason it seems weird is that the upper body equivalent of a heel hook is never used in BJJ. It's not because it's illegal; it's just way too low percentage to work.
The upper body equivalent is something like shiho nage. It's one of those throws you'd see Steven Seagal do in a movie. You twist the wrist, which twists the elbow, which twists the shoulder. The weakest part breaks. You control the whole limb just from twisting the most distal joint.
If anybody in BJJ actually used this type of upper body throw, heel hooks would not be so weird. Then they'd just be the lower body equivalent. Kind of like how a kneebar is not mysterious because it's just an armbar done to the leg.