It was a good pic of a very pretty top. If you wanted an Epic, that looked like a nice one to get. I don't think it was worth an extra $500-800 to get that nice top, but someone did.
I don't think you can really say the guy at $850 short-changed himself since that's been the going rate for average Epics over the last year or two.
One last thought. The two bidders both had low feedback and a negative or two. There could be some eBay ignorance involved, some bogus bidding, or this deal could never go through. The seller offered a return policy as well, so this may be a try-and-return deal. If you really want to know, watch for the next week or two and see what sort of feedback shows up.