Overall, I use "strange WiFi things" techniques for two useful things : audit security cameras, and foxhunting.

I use it to test wireless security cameras on my home network -- to see if I can deauth them and/or force them to reconnect to spoofed access points. If it's easy, then either the router or the cameras are being useless, and I upgrade/replace. Obviously WiFi security cameras can't be made super secure, but if I know how good they are, I can conclude when they are 'good enough'.

I only buy routers that support secure management frames, but I want to make sure that it actually works as it should. I test client networks too, with permission, and then plug security holes.

I also specifically disable secure management frames and deauth my cameras to see how they respond. If the system just 'freezes' without any warning being raised (and then resumes on reconnect), that is also a fail. Connection dropping must raise some form of alert.

Then for foxhunting, I build multiple antennas and listen to traffic. Then I use the RSSI to perform multilateralization on the signal to get a vector on their position. You can get 3-5m accuracy with some work. This is a neat but complicated way to build an indoor positioning system to track employees, corporate assets, and employees that you treat like corporate assets.

Also you can sometimes hack together WiFi ToF measurements but this is tricky and not widely supported.