@goodlistening64 I tend to go the other way. I would not try a cable that was only 15 awg.
That said, it would probably be fine on low power systems or systems with an active bass driver.
Edit to add: I am intrigued by a speaker cable that is stiff enough to stay where you put it rather than lay where it wants to lay. Audioquest has a free in home trial. My system is using less that one watt per channel....maybe I should consider it.
Jerry