I believe finding your voice is paramount to achieving success in stand up comedy. Having great jokes is one thing but possessing the ability to drive them home in a spirited soulful way is HUGE for getting laughs. A stage voice can do that.
I believe your voice is in a few parts. It's part attitude, spirit, fun, drive and what you want or need to do. It's your overall story and philosophy and it should run through your material and performance like a river.
The thing to do is recognize it and then begin to harness the strength and vision of it.