Never underestimate the value of grip strength.
Because grip strength is strength.
Strength only comes when your muscles are activated, and the way your muscles are activated is by your grip. The harder you grip something, the more muscles you recruit; this is a strength training concept called irradiation.
As a demonstration, make a fist. You should feel some slight tightening of the forearm. Now grip slightly tighter. You should notice your bicep and tricep now joining in on the flexing. If you then proceed to white knuckle your hand, you will notice even your pec will start to flex.
If you ever find yourself struggling to press or pull a weight in the gym, try gripping the bar as hard as you can. This concept, of course, isn’t exclusive to lifting weights. When you’re trying to control an opponent in grappling, you don’t want them leaving you.
This is where grip strength comes in. When you can get a good grip on someone, you know that they’re not getting away: