Is it worth it to mine this coin on a Quad core i7 2.2 GHZ?
EDIT: 2670-QM Intel core
As a way to make a quick buck? Maybe, maybe not.
As an interesting experiment in math, science and economics? Hell yeah!
My CPUs would be
crunching primes anyway, so I'm not exactly losing anything by running primecoin instead.
More generally, how do you measure the worth of something, whether it's useful? Maybe thing A is useful because it helps you with thing B. So what's B good for? Probably because it improves C, and so on - you'll never end up with some fundamental worth or utility this way. In the end, we all die, and we can't take our cryptocoins down into the crypt

Personally, I play with cryptocurrencies because it's fun (and I dig math). IMHO, where worth begins, fun ends.