1967 Rickenbacker electric Banjo

Is there any advantage of using an electric banjo as oposed to a pick up in a traditional 5 string & are there many on the market

This one on ebay seems to be quite expensive but I presume thats becase its a Rickenbacker

http://www.ebay.com/itm/1967-Rickenbacker-6000-Bantar-Electric-5-String-Banjo-Bela-Fleck-VINTAGE-RARE-/330653511978?pt=Guitar&hash=item4cfc7c312a