I still don't understand the appeal of revenue-based rewards programs

Invariably when I write about Ultimate Rewards transfer partners, commenters chime in that I've left out Southwest. And this is invariably true: Southwest doesn't serve my local airport, I don't fly Southwest, and I don't like Southwest, so I don't write about Southwest.

But it's worse than that: I don't care about any revenue-based rewards programs.

Hotel revenue-based rewards programs are great — if you're a business traveler

If you're a business traveler who is reimbursed for their paid hotel stays, then it's essential to understand the concept of point "density:" how much you need to spend at each chain in order to earn enough points for award redemptions at that chain's properties.

If you pay for your own stays, on the other hand, then it's vanishingly unlikely that you're going to get a big enough rebate from a hotel's loyalty program to justify paying retail for hotel rooms booked through that chain, as is typically required in order to earn hotel points: after all, you can get a 17% rebate by simply booking paid stays through Hotels.com, after clicking through a cash back portal like TopCashBack.

Of course there are corner cases, like someone who otherwise pays for their stays through manufactured spend, but who is gunning for Hyatt Diamond elite status in anticipation of an upcoming trip where that status is going to pay for itself with suite upgrades, breakfast, or lounge access. But an extraordinary amount of digital ink is dedicated to those corner cases, which are simply not encountered by the typical traveler in any given year.

Airfare is too cheap to think about revenue-base airline rewards

Southwest has a "pure" revenue-based rewards program: you earn points based on the amount you spend on airfare, and then you redeem points based on the paid price of a ticket, after the appropriate conversion rate is applied.

So the ideal use case for Southwest points looks something like this: earn Ultimate Rewards points at 0.5 cents (gas stations) or 0.67 cents each (office supply stores), transfer them to Southwest, where you have a Companion Pass, and redeem them for between 2.5 cents and 3.4 cents each when booking award tickets for yourself and your designated companion, giving you a discount of 73% to 85% over retail.

And if you live in a city served by Southwest, and which serves many destinations with nonstop flights, that really might work out to a pretty good value. Baltimore and Dallas, I'm looking at you.

In exchange, of course, you have to fly Southwest. On the one hand, that means free checked bags. On the other hand, it means furiously checking in exactly 24 hours before departure, lining up for the alphabetical cattle call, and then crossing your fingers that you and your companion will actually get to sit together while the flight attendant raps his safety briefing at you.

Meanwhile, if you have access to grocery store or gas station manufactured spend, you can use a US Bank Flexperks Travel Rewards card to get up to 75% off paid airfare on a distance-based carrier like American, Alaska, or Delta (if credited to Alaska). And in addition to your air travel, you also earn miles that can be redeemed for additional airline award tickets.

That's the calculation that prevents me from having any interest in flying on Southwest, or crediting my paid flights to revenue-based carriers.

Crediting paid flights to revenue-based airlines is the least efficient method of earning miles

A general member crediting a paid United flight to United will earn 5 Mileage Plus miles per dollar spent on airfare. Pay $400 for a domestic roundtrip ticket, with $5.60 in taxes and fees, and you'll earn 2,000 Mileage Plus miles.

Pay the same $406 for gas station manufactured spend, and you can buy 82 OneVanilla prepaid debit cards, earning 82,811 Ultimate Rewards points. That's 3 domestic economy roundtrips at the "saver" level or 1.5 roundtrips at the "standard" level. It's $1035 in paid, mileage-earning airfare — on any airline, not just United.

The difference in scale here is geometric. Go ahead and bump your United earning up to 7, 8, 9 or 11 Mileage Plus miles per dollar spent, and you'll run into the exact same situation: the more you spend out-of-pocket on paid airfare, the more miles you're leaving on the table.

The same is true of Delta: as long as SkyMiles are a transfer partner of American Express Membership Rewards, you'll never get better value buying paid Delta-operated flights and crediting them to Delta than you will spending the same money manufacturing spend in bonus categories on your American Express cards.

Go ahead and credit to Delta and United — just don't do it for the miles

Of course I'm begging the question here: once you've manufactured the spend you need to redeem your miles for paid domestic travel, you still have to credit the flights somewhere.

Personally, I privilege flying American, Delta, and Alaska in order to credit flights from all three to Alaska'a Mileage Plan, but you may well find that United best serves your needs, and decide to credit your paid United flights to Mileage Plus.

Likewise, you might find that Delta Medallion elite benefits make it worth crediting your paid Delta flights there, whether for complimentary upgrades, preferred seating, or refundable and changeable award tickets.

But if you do, don't use the rebate value of your redeemable miles as justification. It's not there.