I haven't ever NEEDED them, but I have used strobe quite a few times. As funkychateau pointed out, it is very good at grabbing attention. There are plenty of places where there are bright lights all around, so merely having a powerful light does not guarantee you will stand out. Strobe, though, catches the eye like nothing else. Even in a brightly lit and busy area, it is an unmistakeable signal.
I agree that strobe should not be part of the regular mode cycle, but it is a useful feature, and it should be easy to access when needed. Choice is a good thing! As long as they aren't in the way, you never have to use them...but why deliberately limit the versatility of a light just because you haven't yet had the occasion to use it?