So here goes resistance training should always be part of everyone's work out plan regardless of your goals if your trying to lose weight, become healthier, get arms like this guy or just open that jar at home resistance work can help you.
Training for functionality is really important if your training goals aren't about image or being some crazy strong superman, resistance training can still help you. A great benefit of being stronger is that you are able to more easily to preform everyday tasks like carrying shopping or taking out the rubbish ect.
But the benefits of resistance training don't stop with body image and functionality, resistance training has also been shown to have health benefits strengthening the heart muscle as well as increasing bone density and can help to prevent injuries by strengthening joints.
It has also been shown to help patients with kidney problems increasing blood flow through the muscle and improving phosphate removal also patients with a greater amount of lean muscle mass have a higher survival rate.
Here is a great article about the benefits of strength training.