I recently used a 555 (and some other simple parts) to fix some timing issue my ham radio's internal CW keyer seemed to be having. Maybe I could have used an ESP32 module that I also had lying around, but I could run the 555 directly off of the ~12 volt power supply, and it was also more fun to build the little circuit.
More details if curious: https://www.reddit.com/r/amateurradio/comments/1eo9ki7/xiegy...