The advantage of buying from a seller that doesn't know what the stuff is and describes it poorly. The other, a much better description with a reasonable BiN price.
Well, here is a similar story:
About 10 years ago, I was interested in buying a drying cabinet. I saw one 2nd-hand, advertised in the local paper (Essex, England) and went to take a look. It was a beautiful piece, hardly used, manufactured by Marrutt, worth about £500 new. The seller, a lady about 70 years old, did not know what she had there, and offered it for £50. I told her what it was worth, but she said that it was old and her husband never used it much. She just wanted to get rid of it. It was tempting, but I just couldn't. I gave her £200 and never looked back. It's still drying my film today.
Again, pay up to what its worth to you. A simple rule that has served me well over the years.