The Special Air Service has many unorthodox talents.All 'badged' members of The Special Air Service are parachute trained; however, there is a need for members of The Regiment to be trained in military free-fall techniques in order that operational tasks such as covert insertion by parachute into hostile territory, from high altitude, can be employed as and when needed.
Note the term 'covert insertion' i.e. landing troops into somewhere without making a lot of noise or otherwise attracting attention. I am sure that we all know the noise levels of military helicopters. Having one hover whilst attack forces deploy down a rope, in a remote area where such noise is rarely heard, cannot be described as 'covert'. The advance on foot to the compound where a hostage might be held would allow ample time for the dissidents to get into defensive positions and plan their tactics.
American special forces were within "seconds" of rescuing the kidnapped British aid worker Linda Norgrove when she was fatally wounded by a suicidal explosion triggered by one of her captors. We cannot know how long it took for the rescuers to get to the compound from their landing spot but one has to wonder why the silence of a HALO insertion was not used. The training of SF allows almost pin-point accuracy of landing; certainly all in the middle of a compound.