It shouldn't effect battery life. Frankly, it is just a preference.
Yes the colors pop using tv gamma, but they are certainly not true to life and you are going to be very sad when you print color and it does not reproduce what you see on your screen.
That's why I prefer matte screens, as well: most people think glossy looks better until they have to do photo or video work, then they realize that the matte screen allows them to see colors and details easier.
(On this subject: I've never understood the attraction of glossy screens on laptops. On a laptop you can not control your environment so glare and light control are major problems. With an iMac glossy, at least you can change the environment around the computer to help with this.)