writergrrrl48: those people are called MacroWhores. :)
Seriously...I'm of two minds on this issue, but leaning a lot more toward writergrrrl's opinion.
The only time they're useful is when they're built for an emotional response, which most people tend to miss completely; they're so busy putting in special effects and whizzes and pops and colours that they forget that a Flash movie is still a movie, and that there's an ultimate purpose to it.
A well-designed Flash intro, in conjunction with a half-decent marketing campaign, can trigger an impact. Just don't expect full
SEO benefits, unless you can somehow work text in around it.