Doing sport is so important because of many reason and it makes you being fit.
One of them is that you can avoid suffering some illlnesses like a heartache, some cancers, but only if you have a routine and you do sport each amd every day and if you have a good diet.
Also we avoid the obesity that today it's a big problem because everybody eat fastfood and they don't do sport, so they begin to be fat and fat. Being so slim is a problem too. So we have to be in the middle point. Being fit.
The attractiveness aspect obviously is another great reason to start working out. If you want to be more attractive you can start going to the gym and eating healthy food, and in a few months you will have results. But this is a superficial reason, because the main incentive is to be healthful.