There is a reason; it because they land where helo's weren't made to land, on the peaks of mountains. Think about it; how big and how solid is the top of a peak? Answer: not very. No way you could land an Osprey on a mountain. Hell, aircraft carrier probably hard enough. The Eurocopter A Star does the job mighty fine.
--------------------------------------
~~Phunkin Phatt Phreerider~~
''doo doo dood doo do da dah dah da, everybody in the house say 'wooooot woooooot', do doo dooo dod doo DAAAAAAh ba ba ba bum bum ba do do do dooo dah dah da, oh yeah, do do do daaa, everybody now, uh, yeah, uh uh yeah, do dah, do do do dooo dah, right on! wikky wikky wack, do do daaa ba dada, mmmmmm yeeeeeeeeah.''
-PhattTim