I shot some #107 office bands without a pouch, using 3/8 - steel, just for the heck of if.
And I've shot .177 cal bbs from unadulterated #64 office bands.
It works, and I guess it could be useful in some situations.
I have not tried it with a decent latex, or even the old Gold's Gym Green. They just seem too thin.
The rubber makes it hard to get a clean release, so accuracy is sketchy.
For an emergency kit, I would pack bands with a pouch attached.