The main selling point of single length irons is that they are simply easier to play.
In a conventional set of golf clubs, each iron is made with a different length and weight…and they are meant to be played from a different ball position as you go from club to club. Golf is already hard enough and conventional iron design only complicates the game further.
On the other hand, single length irons are all the same length and weight. This means you only need one swing and one ball position as you go from club to club.

For the average amateur who doesn’t play regularly, this can make hitting the ball easier and the game more fun.
For the better player and/or professional, you will be able to hit your approach shots much closer, make more birdies, and leak less bogeys. This is especially useful with the lower lofted irons in that 175-225 yard range that is so statistically critical to tour success.
The Sterling Irons ™ in particular are built to be 8-iron length. This length ensures that you will hit the lower-lofted clubs more consistently in the sweet spot…while still not being so long-shafted that it feels odd to be playing 9-iron or wedges that are slightly longer than in a conventional set.
If you want to hit the ball better, shoot lower scores, and have more fun…you should play single length irons.