"Every now and then I feel a temptation to design a programming language but then I just lie down until it goes away." — L. Peter Deutsch
There are several debates as to whether or not it's useful (Rob Conery summarizes and links to some of the more prominent talking points in his own struggle). Personally, I don't care that there is a debate at all. I will use CoffeeScript when I can because it's appealing to me. There's room for different tastes, at least in my world.