Is specialized grip strength actually "functional" for real life, or is it just a party trick that doesn't translate to anything else?

I know firsthand that my grip is stronger than most people who focus on powerlifting, but I constantly get into debates about whether this training is actually "functional."

​Some people say grip strength is the ultimate indicator of longevity and health. Others argue that if you can't deadlift 500lbs, having good grip strength is useless. I’m curious where the line actually is. Is grip strength a distinct, useful athletic skill that people ignore, or is it just a niche hobby that doesn't really help?