I argued with my neighbor about this last year. He showed me how a GFCI can trip from a fault in any old wiring, not just water. Ended up adding a few and it's peace of mind for cheap.
Wait, your neighbor just randomly knew all about GFCI faults from old wiring? Mine just complains about my lawn. I always figured those outlets were just for bathrooms and kitchens, you know, where water might splash. The idea that some frayed wire behind a drywall could trip it never crossed my mind. That actually makes a scary amount of sense now.
Actually, old appliances with worn cords can cause faults anywhere, not just near water. Henry_martin37 is right about that hidden wiring risk, but people forget about the lamp or toaster with a bad plug. It's cheap safety that works for more than just wet hands.