In failing to provide true air cover and support for the ground troops in the Falklands due to its woeful range?
And just how would we have done without them? And, no, we would not have had CTOL instead, CV01 was cancelled long before the idea of the Shar came along.
(I was lead to believe the USMC regard for the AV-8 was that it was close at hand when needed, not 200 miles off-shore. When grunts on the ground needed it, it was there. Like super artillery. In essence, as it was explained to me, the USN and USAF are more interested in minimising aircraft loss rates, the USMC being more interested in minimising marine loss rates.)