Ask HN: Strong magnet in Logitech mouse box

I recently bought a Logitech MX Anywhere 2S mouse and when I was flattening the box I noticed it had a small battery like disk inside. I assumed it was an RFID tag. When I was tossing it in the trash it flew out of my hand and stuck the metal trash can.

On first glance it looks like a "357" battery [that is the small battery a little less that 1/2 across that is very common in laser pointers, small flashlights, etc].

Does anyone know why an RFID tag (if that's what it is) would have such a strong magnet in it?