The level of intensity of a workout IS one of the basics. Sure, while doing something is better than doing nothing, whether you push the muscles to exhaustion

The level of intensity of a workout IS one of the basics. Sure, while doing something is better than doing nothing, whether you push the muscles to exhaustion or not, or whether you push the cardio to max throughput or not makes a vastly outsized difference vs mere total time or effort expended. The details of how &how much you get to that intensity are admittedly details ,but to dismiss the whole concept as unnecessary is, well, unnecessary ignorance. Source: fmr international level amateur &pro competitor & trainer. Happy to provide more details of training if interested .