When I was growing up there was often a phrase my friends and I would use to describe the unexplainable level of strength that many old dudes we knew seemed to have: "Old Man Strength" is what we called it.
We didn't know what caused it but we certainly noticed that our coaches, our dad's, our friends' dads, grandpas, etc, etc could all just grab us when we were misbehaving and immediately render us harmless with their seemingly iron grip. It didn't matter how skinny or old they were or how little muscle they seemed to have; they could almost always manhandle us even when we were lifting big weights in high school and thought we were strong.
The reality is that these old men had super strong hands from many years of labor and regardless of how much muscle we had packed on in football off-season, our hands had not had the level of training that these men had. We'd been working all of our big muscles while holding a skinny little barbell. That's fine of course, nothing wrong with that. The only issue is that very few things in life are shaped like that skinny little barbell which allows you to wrap your fingers all the way around it giving your a solid hold on the weight.
When you're doing things in real life, most things have odd shapes and textures which requires the hands to grip in many different ways. There are
The list could go on forever, but the point is that in real life, the hands have to hold a variety of different objects with a variety of different shapes and if you have strengthen your whole body without deliberately strengthening your hands as well through various gripping exercises then the strength that you have developed in the gym won't be much use to you in real life.
Hand strength is the great limiting factor in the transition from gym strength to real life strength for most people. Don't be one of them. Train your hands deliberately and make your strength useful to real life.