Quote:
Without getting into the weeds...there's a reason why it's easier to hit a full swing 54* on a rope than it is a 4-iron.
Entering the weeds:
If you have a chance to look at Dave Pelz' Short Game Bible, he shows some plots of hundreds/thousands of iron shots. The pattern that ultimately comes about is (if looking from the sky downward to a green)...
...with wedges, the pattern ends up looking like the number 8, with a large amount of shots both short and long, but not necessarily way out to the sides. Reason? As jj mentions above - backspin (or the other way to think about it - less side spin). You don't spray wedges, because it's hard to with the backspin keeping things on target better, but the high backspin makes controlling the distance tougher.
...with longer irons, the pattern ends up looking like a sideways 8 or an infinity symbol. Easier to control distance, but the added side spin (or less backspin) causes balls to go right or left of target. For the average golfer, on a decently struck long iron - it is less likely you are short or long of the green, but pretty close to pin high. Reason you might come up way left or right AND short is just due to poor contact together.
This is why distance control with wedges and the short game (including putting) is most important. You will score more if you learn to control your distance with wedges, and Pelz has some techniques to help do that which resonate well for some people, but not with others. Other teachers have different techniques so find something that works. If you take a general approach to target line with your short game, and focus 90% of your efforts on distance control...your scores will plummet.
This might help....you can be off direction by 50% and still have a tap in putt, but 10% off in speed on putts causes 3 putts: