Another place where mile redemption trumps paid tickets is in the last-minute category. Most times, there is availability in the standard awards category for last-minute trips that work out to be way more economical than a piad ticket. If you are the type of person who waits till the last minute or makes impulsive travel decisions, having the option of using miles helps quite a bit.

But, for the most part, I agree with amolkold in that the value per mile should be based on what you would have been willing to pay for it. While I understand that there are instances where you would have never bought a ticket for a certain price and the only reason you are making the trip is because of miles, I think this is a rare care. As in, say, out of 5 trips or so, there might be 1 where this line of thinking holds true...

Ultimately, you also need to look at the amount of time & energy you put into acquiring miles. As long as you are having fun doing the grind, it's great, but once it starts feeling like a chore, it changes everything.