There is no end to the benefits of weight loss if you are overweight. Being overweight affects your self-esteem which can have an impact on your entire life. It could make to withdraw socially, which causes you to lose out on a lot of potential fun and possible relationships in your life.
Then there are the health benefits. Being overweight puts added pressure on your bones and joints, so weight loss can relieve this pressure.
It also strains your heart and can lead to heart disease which could turn into a heart attack, which we all know can kill you.
Losing weight can also help prevent the onset of diabetes as overweight or obese people almost always get diabetes. Diabetes can lead to kidney failure and so many other health problems that it's scary.
So the benefits to weight loss are many, but only if you are overweight. If you're at your ideal weight or underweight then you should not worry about losing weight.