It all depends on how much you value an airline point worth and how you're using them. There are tons of thoughts on this, but my personal valuation of an airline mile is about two pennies. If the airfare is cheaper than the mileage ticket using this (also including the miles I would have earned if I paid cash), I'll buy the ticket with cash. Otherwise, I use points. So I'd value the 12,000 miles at about $240.

However, there is always the law of diminishing return: For someone with millions & millions of miles, you're better off with the cash that can be spent somewhere other than on an airline ticket.