I gave the example in a recent post:
"Why would I ride a bike when I have a Car?"
It's not that you're choosing to be "worse" as much as you're choosing another method. If you don't have the right gear, combat skill, weapons, etc , then and only then are you handicapping your output. If you can equip a nice dagger and build a TP/Haste build that rockets you to 100 TP in half the time it takes you to get there with a GA, and then swap in some great WS gear that clears 2-3k+ each time with your dagger WS, you should doing similar if not more damage.
I'm gonna have to post a youtube video man >< lol There are folks that just don't try this stuff.