Well, personally, I believe that eBay is just a marketing device, similar to any newspaper, trade publication, broker promotion or any other internet medium.
All are caveat emptor, as is everything else in life.
I would never say that I would never buy anything on eBay, and I find that to be a curious perspective. But then, I certainly don't know everything about everything (including eBay) and I am always open to learning something new.
If I were looking for a larger boat (50') with a great heritage then I would certainly look at that eBay boat, and I would most likely much rather have that boat for that money than almost every other trawler or (non-Hatteras) motoryacht that could be bought for a similar amount of money. And those naturally aspirated engines would not scare me off at all, subject to survey of course.
All in all, that 50' eBay Hatteras seems to me like it might be very much worth considering.
Disclosure: I have no financial or legal interest in the boat, I do not know the owners, and I have never seen the boat. Just thought the HOF members might be interested in seeing what's out there.