Surely an advantage, far less faffing around pellet testing
Actually there is quite a reasonable amount of hydrostatic shock (soft tissue damage) even with sub 12 if you cross section the wound channel.
(that may not be true of .177 I don't know, I don't use it)
As usual on the subject I refer back to the 4 calibre comparison from AGW,
.20 happened to be the most efficient sub 12 calibre.
Those of us who shoot it know how good it is as a hunting calibre,
I strongly suspect many of those who rubbish it, will either have never used it or only on a target range