I think there are several ways you benefit from endgame study.
Your middlegame can benefit: For a beginner player it is often easier to process an emptier board with few pieces. The limited move options and plans then can help to focus on main concepts or ideas.
For instance if you learn to mate K+R vs K, you will learn how the pieces move, which squares are "attacked" (unavailable to the enemy king) and that in order to win you need to checkmate (take away all possible moves from the king and attack it). Also you will learn about zugzwang. All of this can be useful in the middlegame as well.
As another example you will learn that isolated and other weak pawn structures are things you don't want to have in an endgame, so you will want to avoid them in the middlegame (unless you get another advantage in exchange).
Also the importance of piece activity is usually pronounced in endgames which could make you pay more attention to it in the opening/middlegame.
It can make you win equal positions (or hold lost positions) ...if you are much better in endgames than your opponent.
It can help you decide whether and how to change from middle to endgame If you know that an endgame position is won/lost/draw, you might or might not want to go for a line in the middlegame that leads to that endgame.