Well, yeah, there are limitations to everything. They're not going to work on stolen devices when they're overtly advertised in cutesy keyfob holders that say "throw me away first". Use your brain because you have to disguise
them on some objects.
AirTags and Tile Pro work fine wherever there are other people. They're not going to work in the Atacama.
They worked fine every time I used them. I recently sent a laptop to France and included one of each. Sometimes the Tile pinged and sometimes the AirTag pinged, but they worked really well across continents.
I also have about 4 of each in a vehicle left unattended for a while in a parking garage that doesn't have a great deal of people around it. And all of them ping at least once a day. The Tile Pros have ~100m LoS range which are quite a bit more than previous ones from years ago.