I keep a card around like this. I use it once a year so they don't close it for inactivity, but it's a non-reward card so I don't use it day to day. It has a 8.50% APR from two decades ago, so I keep it around just in case. I can't really see where I'd actually need it, but it costs me nothing to keep it around.
It has bailed me out of paying high interest rates and fees during hard times before.