<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by channa:
There's also the value aspect.
I bought a coach ticket SFO-LHR for $326. I'd be insane to blow 50,000 miles for that trip (less than a penny a mile).
A First Class ticket SFO-LHR costs $10,000. Using 100,000 miles for that seat is 10 cents per mile in value.
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This is absolutely the reason people do it.
If you don't fly in business or first class on business, chances are fairly high that you'll never get the full-on travel experience, since you won't want to part with so much of your own cash for what amounts to spending 8 or 10 hours in a metal tube.
However, if you are using a more opaque currency like miles, you might be more inclined to do it.
As the math above show, premium class travel is relatively cheap using miles.