Are you confusing the specs for o-rings used to seal things from fluid and/or gas leakage with specs for using as rubber bands? Even so, there are many different specs for O-rings that operate in different environments. IE, space shuttle booster vs air chuck on floor pump.

Didn't see anything about UV resistance in your specs. Maybe that's an issue for those companies using O-rings that were only intended to seal.

As suggested, cut up an old inner tube o use nylon wire ties (tie wraps).