IIRC, the 1979 Fastnet yacht race disaster showed that winching up a survivor who had been immersed in the water for a protracted period could possibly instigate a cardiac arrest, if performed in a vertical posture using a strop. This is due to the sudden drop of hydrostatic pressure acting on the body when lifted clear of the water, which will put the heart under considerable stress. At least one man in the Fastnet race died in exactly these circumstances.
The basket lift, in a horizontal posture, greatly reduces the stress on the heart when lifting the casualty clear of the water. This could be crucial when dealing with injured/aged casualties in such situations.
HB