Like every other digital camera (unless it's SLR), digital zoom destroys the quality of a photograph. With low-to-middle end digital cameras, you'll get much better photos in daylight, and using little or no digital zoom at all, especially on a camera phone.
Example...
This photo was taken with my Q - no zoom in medium daylight. No post-editing, whatsoever - just straight from the Q. Not bad, right?
With a camera phone, you have to have an extremely steady aim/hand, because the camera phone's shutter speed isn't able to keep up with any motion. You can get away with getting a decent photo with 2x, maybe 4x on a great day, but many nighttime and 6x photos look god-awful. It's not the phone's fault - it's the way digital photography works...
See the difference in picture quality?