There are a few different reasons that make people fly on MRs. As clacko mentioned above, they're not usually for RDM, the miles you're talking about in the first post. The RDMs tend to be more of a bonus/offset than anything else; for example, let's say that I fly from BOS->LAS and hit about 5,000 miles on the flight through a connection. After bonuses for being an elite, that's 10,000 miles; I fly DL, so even with their limited value, I've "earned" a minimum of $100 with those redeemable miles for a future flight. That can offset the cost of flying somewhere quite a bit, to the point where that $200 flight to Vegas comes down to $100 and makes it easier to justify spending 24 hours in town. And if I find a sweet spot in an award chart and can redeem my miles at 4-5cpm -- which happens with enough planning and know-how pretty regularly for people here, I would imagine -- those miles that cost me $200 to acquire ended up producing $400-$500 of value. When you think about MRs that way - as a way to spend a small amount of time in a place for far less than it would otherwise cost, with the upside of creating opportunities for trips I couldn't otherwise afford - it makes a lot more sense, to me at least.