I heard that it was a COVID feature. I guess people thought you would be scanning your friend's foreheads before socializing.
That sensor would be much better if it was integrated with the camera and LIDAR, so that you could "paint" a scene with thermal data by moving the phone around.
The sensor is damned handy because it has plenty of range and good options in the software for estimating emissivity. I use it in the kitchen.
That's the only plausible scenario, but it also came out in 2023 and people stopped caring at least a year before. And it persisted for a few years so either someone thought they could salvage something from it, or no one had a better idea what to put there.