Although figures seem to vary, there is evidence that dog domestication began at least 30,000 years ago. Dogs co-evolved with humans to the point that we can communicate with them to a really impressive extent - humans can understand dog emotions and vice versa. It has also been shown that dogs can understand human pointing, a feat that even chimps are unable to accomplish, and I don't see any evidence of pigs doing the same either.

Dogs have been used for hunting, pest control, guidance (as in guide dogs), and companionship (individuals with PTSD or emotional problems) amongst many other uses. I have never heard of pigs being capable of any of these tasks. Their only other major use appears to be for truffle hunting.

I do not eat pork and I respect that pigs are highly intelligent creatures, but to claim that they are "way smarter" than dogs is absurd. To insinuate that we should eat dogs because they are supposedly less intelligent than pigs is even more ridiculous, and shame on anyone who thinks that. Without dogs, many human populations would not have survived, the Thule and Inuit being prime examples.

All of my claims are backed by this video, which does a lot more to explain how amazing dogs truly are: http://www.pbs.org/wgbh/nova/nature/dogs-decoded.html