Button Jacket

What is the button at the bottom of the North Face Denali jacket?

I bought a North Face Denali jacket … and I'm so confused, what is the small button on the End of each sleeve for. It was bothering me, what it is:)

IK I do not personally have one but my friends have them (and I would like great 1!) I asked them what were they and what is said to secure gloves on the sides.

Miss Tina Stretch Denim Button-Front Jacket