So what accounts for the continued appeal of the airline credit card, and who ought to have one?

Some things that have always been true about these cards remain so: If you travel a lot on the same airline and spend a lot of money in your everyday life, earning the same reward currency when you travel and when you’re using your card can help you quickly earn more and better free trips.

But things have also changed. In addition to the miles, many of the mileage cards now come with privileges. You might get a free checked bag. Or you can board your flight in the fifth group instead of the seventh, thereby getting space for your carry-on in the overhead bin.

This is clever and ought to inspire some healthy cynicism. After all, the airlines created the problem that the cards are now solving by charging for checked baggage. Now, for an annual fee of $95 or $150 or $450, you can avoid multiple $25 or $35 nicks for checking bags. And even if you can’t be sure what a free flight will cost in miles, at least the baggage giveaway is something tangible.

“As points become more confusing and devalued, people turn to perks — and they are easy to see and easy to value,” said Brian Kelly, the founder of The Points Guy, a website that makes money from referrals by channeling consumers to the most useful cards. (Wirecutter, a New York Times company, has also made money this way in the past and plans to again in the future.) “The issuers are doubling down on perks, and it appears to be paying off.”

The card offerings are now complicated enough that it’s nearly impossible to offer generic advice about who ought to have one. For me, the sign-up bonuses for the Delta and American cards plus the baggage fee waivers on Delta were enough to persuade me. The top-tier American card also comes with airline lounge access, which I finally treated myself to (and deducted on my taxes) after too many years of hacking together standing desks at abandoned airport gates so I could work comfortably on my laptop.