a dog have a better quality of life and lower mortality.
My wife and I are new empty nesters. It took some convincing to get her to want a dog, as she did not grow up with them, while I did. We tried a cat, and got rid of it when she peed all over the spots where our first child was, as a sign of jealousy and territory marking.
A dog for us is something to love, serve, and who loves us back. We get out to walk him twice daily. He is expensive, but worth it.
Not in our circumstance, but many are lonely, and a dog provides that need for companionship. As mentioned before, the reason why we chose a labradoodle was for low allergy and no shedding. Any type of dog can provide the benefits that people need, especially as they age.