What is a wrist band for

Ok, i always thought a wrist band is to protect your wrist during sport activities right?

But recently, i just found out shockingly that wrist band is actually - "for you to wear it on your hand to enable you to wipe your sweat away conveniently at anytime during sport."

So you don't have to bother about bringing a towel.

When i heard this, i got a shock in my life, really meh? Isn't the only purpose of a wrist band is to protect your wrist?!

Ppl, please shine my light on this because i don't want to look like an idiot when using a wrist band to wipe my sweat during hiking. Very xia sui if the theory is wrong leh.