Everyone has their own view of the cost/benefit analysis. I have one of the higher end travel cards that comes with a hefty annual fee, but when I break it down to calculate what I get for that money, I come out on top without even counting the SW points I trade my points in for.
In additional to free global entry (and therefore precheck), I get access to airport lounges for me and two guests (a delay is much less painful when I have a comfy place to hang out with free food and drink), the card refunds the cost of the peloton app, I get discounts on Lyft, statement credits for doordash, and there are a LOT of categories of spending where I earn points based on a multiplier.
I travel pretty frequently and I've only paid cash for 3-4 flights in the last 6 or 7 years. I only had to pay cash because SW didn't fly to the airport I was going to or I needed a different time of day than SW offered.
That said, I realize many people wouldn't see the benefits in the same manner that I do and/or may not be comfortable using a credit card for the benefits and paying it off every month.