I believe the lack of extraneous features is the appeal; the Flip is successful because the user accomplishes their goal with only the most minimal effort.
Just trying to speculate as to what the most important aspects were. History is too often rewritten later by writers who didn't understand why something was popular at the time that it was actually taking off. So they just pick whatever glamorous reason sounds the most revolutionary.
He may be right though.
Some basic features wouldn't hurt, such as an optical zoom. Otherwise, I would consider buying one.