That's why you put it up for auction - to see if it's worth anything to anybody else. You don't have a plan for it, so why keep holding onto something you don't even know is worth anything?
The internet is filled with worthless 5 letter .com names. Having 'biz' with some random letters only makes it valuable to people who think 5 letter .coms with 'biz' in them have some inherent value. The only way you're going to find out if those people exist is to put it up for sale.