Elastic loop inside pocket of pants

(also posted in rec.backcountry)

I have a Columbia GRT convertible pair of pants. The right pocket has
an elastic cord loop attached to the seam inside near the bottom of the
pocket opening. The loop can stay inside, invisible on the outside or
it can be pulled out. My guess is that it can be useful to hang keys
using, may be, a carabiner, though I suspect the contrivance has better
uses. What can this loop be used for?

Don't you just hate it when your clothing doesn't come with
instructions?

I am fairly certain that in the near future some clothes will come with
instruction manuals/booklets. The tag mentions zippered security
pockets, packagable and such terms which were unknown to me until I
investigated. I have had similar experience with a ski jacket - I
discovered new features after years of use!