Ethernet cable is a high quality cable usable for various other purposes. That includes low voltage power line, such as 12V from the car to phone charger in the house, solar panel wiring, basic tripwire alarms, command relays in the yard from the house, basic audio intercom with your neighbors when phone lines are down, etc.

Plus the obvious ethernet repairs: lines broken by fallen trees/branches in a storm, video camera cables cut by thieves, install new survillance cameras, move existing ones.

Self-supporting ethernet cable is also a decent clothesline when your dryer is not working.