Lifting weights is not classified as a cardio workout, it is resistance training for building muscle.
Benefits
Increased muscle mass: Muscle mass naturally decreases with age, but strength training can help reverse the trend.
Stronger bones: Strength training increases bone density and reduces the risk of fractures.
Joint flexibility: Strength training helps joints stay flexible and can reduce the symptoms of arthritis.
All the essential nutrients can be found in a vegetarian diet! (Coming from a vegetarian herself :))