I’m pretty sure this isn’t the only effective workout for leanness and strength, after all there are lots of strong lean people who do something else. I think it’s being advocated as the “most bang for your exercise buck” (particularly attractive for those of us uninterested in spending much time at a gym) rather than as the only option. Give it a try and see how you feel but for the long haul I think whatever exercise you actually enjoy doing is the best bet.
