system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is height the only biometric used to determine if you can ride a ride.

Carnivals and theme parks will often say "you have to be this tall to ride". Why is height the only important factor when riding a ride safely? Wouldn't many other metrics also be important?

*EDIT* So it appears that the other biometrics are considered when allowing someone to ride. The height metric is more visible due to lack of offense. Others have pointed out that too tall, too heavy, too wide of a waist, and more are all factors that can prevent a rider from riding.
gpt
Height varies a lot and very short people - children, usually - won't be properly held in by the ride's restraints.

Very tall people and very fat people also might not be able to ride, but they will be a lot less common. But theme parks are full of children who might not be tall enough for some of the rides.