On the way home from a trip in December, I dropped an AirTag in the pocket my 3-year-old's stroller and forgot to attach it securely before I gate checked the stroller.
I got the stroller back when we arrived but realized a day later that the AirTag slipped out. I could see it at the AirPort but an ~hour of time trying to recover it wasn't worth it.
I put it in Lost Mode mostly for kicks and when you place it in lost mode you can give people a way to contact you. I left my number.
I watched the AirTag go from my home airport to Scottsboro, Alabama and I knew the lost luggage store was there, so I was confused.
A week or so later I got a call from a service company that handles lost and found for Southwest Airlines. There were able to use an iDevice (presumably) to get my contact information since I had placed the AirTag in Lost Mode. They mailed it back to me for the cost of shipped. I assume if they don't find the owner it goes to the lost luggage store mentioned in the article.
Apple is pretty careful about preventing that, unless you put the airtag in lost mode and enter your phone number.
There are some news stories about people who have had success getting their bags back using airtags. Yes, the airline does give them the runaround, but with a little persistence, and finding local phone numbers for the baggage office at the airport in question, people have had success.
I think it's just useful for extra peace of mind or information when your bag does go missing.
I see Air Canada has launched a feature on their app which actually tells you where your bag is (based on scanning the regular barcode tags). It's really just the info that the airline has, but I think they did that in response to so many people putting airtags in their luggage. Strangely, passengers like to know where their bag is when it goes missing, and quite often the airline's staff aren't that helpful.
I should say that the only time my bag went missing, it was simply because our connecting flight had been cancelled, and the rampies were slow getting the bags off, so we had to wait for an hour and it eventually came out. I only fly about 5 times a year, so I guess people who fly a lot might experience it more often (or, they just have carry-on bags).