The Diamond is a flexible offensive set that uses four players on the perimeter and three players inside. It gives the offense plenty of space and allows players to work together through dodges, picks, screens, and cuts.
There are a few reasons to use this set.
First, midfielders may need a quick breather during a game. The Diamond gives them an opportunity to catch their breath while the attackers inside do more of the work.
Second, the elbows create a lot of space for defenders to navigate. This area can be difficult defensively because there are fewer field lines to help defenders understand their positioning.