Having good mechanics enables you to hit you putts solidly, helping you to learn distance control. Being consistent in your motion also imbeds a sense of trust and belief in yourself that help your overall putting. Being able to roll the ball at the proper speed takes the pressure off of your stroke, particularly on the short putts. Putts that have good speed tend to hold their line more often. Golfers who have good feel can stand over putts of any distance and sense that the putt will go in.
All good putters believe they are good putters.
This confidence in themselves frees up the body to execute a good motion and relaxes the muscles allowing them to stroke the putt at a good pace. Spend some time attacking each point of the putting triangle and your overall putting will improve.