RE: Is it necessary and what is/are the advantage(s)?
To clarify further; when I say large heads in the context of my post, I am specifically referring to the large "winged" versions found mostly on the mechanical heads.
If in the hands of a shooter who is a reasonably skilled shooter and who will still put the emphasis on accuracy and best shot placement, I do not hold the same aversion as I do knowing that such type of broadhead is being used by those who do not care to put the time in to become very skilled shooters, and believe the size of the head and the large hole they make is all that is needed to kill a deer.
I am unswaying convinced that some shooters are of the mentality that all the he or she has to do is just hit the deer somewhere with a large winged blade, and because of the massive wound, the deer will surely die quickly or in close proximity. They are out there. Just read between the lines of some of the people who use the heads or intend to use the heads.
Such false belief is stoked when someone using a large winged head shoots a deer intentionally or unintentionally in an area of the animal that is universally not a shot anyone should take, and the deer just happens to be killed.
How many threads and posts have we read where some shooters have stated that they went to to such a large winged head for the primary purpose of a better blood trail, as though the head will now eliminate the need to develop and refine post-hit tracking skills? A better blood trail is not guaranteed, and following a blood trail is not the only way to track a wounded deer.
Too much of today's technology is diminishing the overall skills that all bowhunters should develop. Sort of like: how many kids can add or subtract theses days without a calculator, or know how much change you have coming if the computerized register glitches.