I had to take care of one of those accessory-size-bred dogs, and holy shit what a dumb breed of dog it was. The shit was sad enough as is, after all the genetic mutations it took to create it, at it's healthiest it sounded like a person trying to snort teaspoons of water just sitting there, but on top of bumming me out miserably, it didn't do anything but need to piss every 4 minutes, and drink water so rapidly it would choke to the point of violently coughing untill it pukes, only to continue drinking. And anywhere I went it would just fallow me at my feet. It was awful. Just making my way through the house was like walking around with a skip-it that I could accidentally kill at any given moment.
Lately one of my best buds has been having to blow everyone off cause' his parents will leave town, and he has to watch his dog, all weekend long. I'd be so bummed on my cats if I couldn't just leave them for a day or two with food of plenty and come home to find a house not completely peppered with cat shit.
Plus, if you choose to, you can let your cats outside. Things would be so fucked up if people just let their dogs out to roam the neighborhood at their dog's will. And after all the cats I've had, I've never had to have one put down because it mauled some stranger. Also, I've never had to take them on walks, and if I did, I doubt I'd have to restrain them from fighting and getting all in an uproar over just seeing another cat on the street.