Every aspect of the fundamentals is important and each one needs to be understood clearly.
The proper grip can make your association with the club a positive and good starting point. The only thing that will contact the ball is the club face and the only thing that touches the club is your hands.
Most new golfers, as well as many experienced ones, tend to hold onto the club in a comfortable way and that appears to be the beginning of a poor grip. When a person has a comfortable grip, there is a good chance that the position of the right hand is not in the correct place. The word comfortable, or maybe the word natural, usually takes us to a bad position of the right hand for right hand players.
When your right arm hangs loosely by your side, the palm of your hand is facing inward toward your body. When a person picks up a golf club, they most likely will put their right hand under the club with the palm of the right hand facing upward to the sky. The grip feels strong and secure, but the position of the right hand is not in the proper place. The right hand sits on the club in the ends of the fingers of the right hand, the same angle as your hand was when it rested beside you. This, in turn, feels uncomfortable to most players as they now feel less secure. However, the right hand should now be correct. Teachers are after the correct position of the right hand at address and throughout the swing rather than the playerbeing comfortable.
The old saying about the three most important words in real estate; location, location, location, helps my three most important words in golf. They are position, position, position. When your grip, body angle, swing arc, body weight or anything else is out of position at impact, chances of meeting the ball on the sweet spot or the middle of the club is unlikely.
As a player swings the club head back to the ball from the top of the back swing, their body cannot move up or down or forward or backward as they will have changed their hitting position from address. Poor ball contact usually means you have moved some part of you out of position and you can no longer contact the middle of the club head. It only takes a small position change to create bad shots.
My advice to those players who want a good grip is a simple procedure. Put your hands on the golf club as you always have. Lift the club head straight up to your belt buckle and cock your wrists slightly up. Without moving your head, see if the second knuckle of your right hand is visible. Most people can only see the first knuckle as their right hand is too far under the handle.
The adjustment will require you to move your right hand more on top of the club just as it was when you let your right arm hang beside your body without the club. All changes require a period of time for development and only a percentage of players will allow for that time. So hang in there and find out what is right for you and work on it!