It's an interesting thought, though - hunting aside, if she enjoys using her nose, then it could be that you did some trailing type thing or some sort of nosework for a scent (eg catnip) with an active indication and the muzzle was twinned with that. It's not something she needs her mouth for, but she'll be doing something she enjoys and it's not just feeding her with it on. She'd get that time spent wearing it while busy (so not actively thinking/worrying about it) but with some independence.
Other than that, I'd just go out for a walk with it and put it on for a few seconds here and there. Pay heavily when it goes on, leave it on for a count of five while you walk, call her over and take it off (working on paying into your recall as well, extra bonus) and repeat, a lot.