I am always amazed when people show up for a lesson and their clubs are filthy. Unless you just came from a practice session on a grass range, your clubs, especially your clubfaces should be clean.
Grooves on your irons are very important, especially on your scoring irons (8 iron to Wedges). They are what helps to create spin on the ball. Spin on the ball helps you hold greens.
Dimples on a golf ball are there to create lift and drag as the ball is spinning. It’s what helps keep the ball in the air.
If your clubfaces are dirty you can not spin the ball as much, if the ball is not spinning as much, we call it knuckling, you have no idea how far the ball is going to go. Sometimes it can go farther, sometimes it can go shorter.
By keeping your clubfaces clean, you have a better chance of spinning the ball more consistently, which in turn should help you have better distance control with your irons.