This is an absolutely first class article on the genetics of strength training by champion lifter Greg Nuckols. It’s long and has a little bit of science-y complexity, but it’s a manageable read for most people. Take your time with it, and really try to absorb what he is saying. There is far too little of this kind of analysis and writing in the fitness sector.
Strength training has too many benefits to list (but some biggies include improved cognitive health, improved self-esteem, and decreased mortality risk), and many of them don’t necessarily depend on the hypertrophy and strength gains you make; many of them come from the process itself. Perhaps the biggest benefit is that continued strength training will help you age more gracefully; muscle strength and functionalitytends to drop off faster with age than muscle mass itself, due somewhat to neurological changes, but primarily due to disuse (which also precipitates some of those neurological changes). Continuing to lift may not help you build much more muscle and strength, but it will help you maintain muscle, strength, and functionality as you age.
Genetics and Strength Training: Just How Different Are We … http://strengtheory.com/genetics-and-strength-training-just-different/