Overly specific use case: I used to have to reach under my desk to find the power switch of the power strip that my monitor and speakers are connected too. I got a Zigbee-enabled power plug, but I thought needing to open the app everytime is also annoying. So I got 2 NFC cards (transport tickets that usually get swallowed by the machine after use, but if you don't use them then, hey, cheap NFC tags!), and programmed Tasker to talk to a HTTP server on my NAS when my phone notices these NFC tags. The backend talks to the Philips Hue hub to switch on/off the power plug and then sends a Wake-on-LAN to turn on my desktop PC.