I think blaming Cryptokitties for the speed of Ethereum is the wrong idea. Although it seems clear that they're a major cause of current speed and fee issues, ultimately this is Ethereum's fault and Cryptokitties are a perfectly valid use of the blockchain. The kittys are just highlighting a weakness of the cryptocurrency.
Although I've obviously heard of them before, just after reading your post was the first time I've really read up on them.
While I'm not really drawn to actually own a cryptokitty, it does seem like a fairly smart use of Ethereum's smart contracts. The idea that the cyrptokitties can exist, breed and be traded independently of the creating company is an interesting concept, and I can see something of the allure of owning a verifiably unique cryptokitty.
That said I'm of something of a loss to explain the huge sums of money some of them are going for (
https://kittysales.herokuapp.com/ ). I suppose it's possible these sales are fake. Or it's possible that there are some early ethereum adopters out there with a huge willingness to gamble. Or perhaps I have it all wrong and they'll go down as a shrewd investment.