I can see the strategic advantage in it- you can sit out there and sweep until near death, and you maintain an offensive threat until the very end. They also tend to be very powerful. They also pair well with the electric type, which has so few weaknesses.
That being said, I would never use them. This will sound dumb, but I don't treat my pokemon like that, I never push them to the point of fainting and I try to avoid them getting knocked out whenever possible. I want them to have max happiness and I honestly kind of agree with N, I don't see the point in having the pokemon battling. I want mine to be the strongest and I want to capture them all, don't get me wrong, I just realize that in a fight between trainers one of their sets of pokemon will come out losing happiness, just to prove their pokemon was stronger. I wish there was an option to "withdraw" your pokemon, instead of being forced to fight to the point of fainting.