There is no right or wrong answer as to whether it's better to pay 50,000 miles for a coach flight or 150,000 for first class. Likewise, there's no right or wrong answer about whether it's better to pay $500 or $20,000 for those tickets, or $50 or $5000 for a suit, or $30 or $6000 for a handbag. If you pay more, you get more; each individual gets to decide whether the difference in what you get is worth the difference in price; reasonable people can disagree about what's better for them.

There are other decisions, however, that don't work that way. If you can buy the same thing for $100 or for $1000, and it really is the same except for the price, a rational person has to pick the $100 price; I can tell you that choosing to pay $1000 is just a mistake, without having to find out how much you like Blue Label or how much you hate sleeping standing up. If people ask for help in comparing options, and they are making a mistake about a decision like that, but where the dominance of one option is less easy to see, it should be pointed out to them.

People on the pro-coach side of this little debate may say outright irrational things now and then, but absolutely irrational arguments make up a sizable fraction of the pro-first discussion. It's fine to pay more to get something you actually like more, if you want to; but it's not rational to choose a Motel 6 in Cleveland over the Westin Tokyo just because, for some reason, the rack rate at the Motel 6 is higher.

IMHO.