The people who buy this stuff have not researched much of anything of value.
To your main point: I began at age 66. I'm 5'10" and weighed 215. My waist then 44,and chest 46. After nearly 6 years of lifting I weigh 226, waist 39, chest 49. I do very little cardio outside what the lifts themselves do for me, once a week 1/4 mile on the treadmill, and once every week and a half I push the prowler around 480 feet. I'll take it.