It isn’t a must to lose weight unless you are morbidly obese. Weight affects many parts of your body, like knees and breathing. Some people are already too thin and some are just right or slightly too heavy. They don’t need to lose anything. When you are overweight, the ankles and knees can end up having a problem. Your heart may need to work harder than it should.
The advantages of losing weight are many. You can buy smaller clothing that looks better. Not needing plus-size clothing means it is easier to find things.
Your shoes will be looser with less fat. If you fall and EMTs need to pick you up, it will be less embarrassing for you and easier for them. You can be more mobile and stay out of a nursing home longer. You may improve your love life if you have or want one. If you combine exercise with weight loss, you can climb stairs more easily.