Is weight training always beneficial?

Yes but dont push it: Weight training is great to improve our muscle tone and take the pressure off our joints. Just start with low weight and increase slowly. The folks who run into trouble are those trying to impress their friends by lifting too much, leading to torn uscles and tendons.

Yes: To some degree it is important to weight train. As we get older we lose muscle. If this cycle continues we lose support for our skeletal system which makes you more prone to falls and subsequent injuries.