I’ve said this before and it bears repeating. Burning calories is least useful way to measure why any activity is useful. By extension why muscle is worth working towards is not measured by calories muscle spends while resting. But by a measure of how useful is the adaptation. 

Muscles contract and produce force. That’s the simple reason we want it. 

Fat cannot produce force. It is a terrific store of energy. And that’s pretty much it .

Producing force effectively and consistently requires you to contract a muscle, send force through a tendon to a joint that produce movement. And doing this several times a week using every major joint in your body is a necessity for high quality of life. 

This is the only pitch one should need. 

You are sold on a house based on security, location, layout, conveniences and price. You never buy a house solely for amenities. 

Buying into muscle for the sake of the energy they can spend while resting is akin to buying a house solely for amentities. While nice, it shouldn’t be the primary motivation or rationale.