I have a dog friendly listing. I honestly can't tell you if it helps because it's always been dog friendly so I can't compare to anything else. There are just too many variables to know exactly what makes my listing attractive to people. Very few people have pets with them, maybe 10% of my bookings. I also board dogs here and although their space is separated from mine it means people who are afraid of or allergic to dogs are probably not choosing my listing. I've had more than 200 guests and not one bad experience. I'd like to think dog-friendly people make better guests.
That's the good news. The bad news is that pets may cause damage, they may shed, ordinarily housebroken dogs, especially males, will mark. And the owners might not even know it. Whether I would recommend it would have a lot to do with the property you have. Why are you considering allowing it?