Increase potential for fat loss
When you combine increased muscle mass, more satiety from your meals and an overall higher metabolic rate due to extra muscle and the thermic effect of eating more protein, your body has more potential to lose body fat. You still need to be in an over-all energy deficit to lose body fat, but having this combination of factors makes dieting much more effective and easier to sustain than other methods of body fat reduction.
Gain more strength from your training
If you are involved in activity that requires a certain level of strength, then expect your strength levels to increase with increased protein intake. This is due to the combination of extra muscle development and quicker recovery from your training.
Better quality of life
If you want robust health and the ability to perform well, then strength, mobility, muscle mass, staying lean and having good internal functionality are vital. Increasing protein intake alone will not deliver all these benefits. However, as part as an overall diet and fitness program, it can have a significant impact that will give you a much better quality of life both now and as you age.