The leg press can help you improve your squat and develop every single lower-body muscle... if you know what you're doing.
A lot of lifters don't. Too often, you see people stacking on mountains of plates only to violently perform a couple of half reps. Or quarter reps. Or micro-twitches. If you're not controlling the weight, you could screw up your back by letting your pelvis roll up at the bottom portion of the lift.
Try out some of these variations using a time under tension (TUT) tempo approach to make the leg press safer and more effective.
This variation will engage your adductors (groin muscles) to a greater extent.
This variation is excellent for extra glute and hamstring engagement.
This variation will blast your quads.