There should be no argument about this question whatsoever. If we are discussing, from a strictly scientifically/physiological based perspective, there is a huge amount of research now showing that resistance weight training is, by far, the best exercise you can do for your body, period.
Muscle is metabolically active. Therefore, the more lean muscle mass you have on your body, the more calories you will be burning 24/7. That means if you are overweight, you're going to be burning the fat right off of your body as you work to increase and/or maintain your lean muscle mass. And there is one type of exercise that is far superior to all others when it comes to accomplishing that - resistance training with weights.
Just look at the body composition of a yogi or anyone else that only does yoga for exercise and compare that to an individual like a sprinter. Why is there such a difference in the appearance of these physiques? It's because sprinters train by doing two things.
1) They do HIIT or High Intensity Interval Training - that is they train by doing wind sprints, running all out for a distance, and then switching to running at a slower pace over a longer distance, then doing more wind sprints, and then switching back to a slower paced run.
2) Sprinters also do a lot of resistance training with weights. These two types of exercise, HIIT and resistance weight training are what give them their physique.
I'm not criticizing those of you that choose to do yoga. If yoga does it for you, that's great. However, doing yoga will never get you into the type of physical condition that high intensity resistance weight training will.
And by the way, there are professional bodybuilders, men that compete at 240, 250 pounds with only 3 or 4% bodyfat who can do the splits on stage. That's pretty supple, in my book.
So, in conclusion, think about all of the activities that you need strong muscles for. Your two largest muscles are your glutes, that is your butt muscles. If you didn't have those muscles you wouldn't be able to walk.
Your neck muscles make the turning and bending of your head possible. Your biceps, triceps, deltoids, lats and thigh muscles make the lifting of heavy objects possible. Why wouldn't you want to make these muscles, not necessarily much bigger, but a lot stronger? Stronger muscles means an overall healthier individual.