Are consumer digital cameras useless for diving?

I've noticed a couple of questions regarding dive cameras so thought I'd
continue the trend. A friend spent $700 on a 6mp cannon camera with a dive
case. I've noticed most of the pictures suffered from a severe lack of light
and the camera automatically went to a long exposure causing many of them to
be blured. Those that weren't blurred were quite dull. Only closeup shots
were acceptable really. After having a look at the pics I'm kinda of the
opinion that only a high quality camera with a full size lense (to let more
light in) and a good external flash would be required to get acceptable
photos. Is this true? I'm not a camera zealot if anyone is wondering as I
quite happily take shots out of the water with a compact and reckon it is
pretty good. I usually dive around the 18 metre mark.

Here's some examples:
http://mikesdriveway.com/misc/dive2.jpg
http://mikesdriveway.com/misc/elizaramsden124.jpg