Compound exercises are actually vastly superior to isolation exercises when you want to build muscle and they are also important for functional fitness.
Isolation exercises only work one muscle group whereas compound movements work multiple muscle groups.
This helps with increasing an anaerobic response in the body, because you are engaging multiple muscle groups at the same time, which, means that strength training workouts can help to burn more fat.
Functional fitness is the use of exercise moves that mimic day to day life and train muscle groups to work together, and that is where compound exercises serve you best by improving performance in daily activities, and eliminating risk of injury, something especially important as we age.
Balance is something often overlooked by people when they design their fitness regimens. Balance training also allows for healthier aging, can go a long way to avoiding the typical falls seen in seniors, and is something that is a by-product of many compound exercises.