Take an employee in a company for example. Companies will often spend big budgets on "Learning and development" programs that are meant to improve the capabilities of their employees. Often the measure of the impact of this training for the employee will be in the form of qualitative measurements post the training with the newly trained individual completing a feedback form. Having the trained employee rate their capabilities and the value of the training though is a flawed metric. Think of it as the concept this article opened with which is Transfer. Unless we can measure that this training has transferred and the employee is now operating at a greater capacity in whatever domain the training was designed to improve, any other measure is basically an opinion. Opinions, as we know are not a reliable source. The training is really only successful if we can have some empirical evidence that the training has transferred to improved performance, leading to improved revenues for example.
The same concept applies to your weight training. Now admittedly we are talking about competitive athletes here. For the regular going gym rat who just wants to put on some size and look good down at the beach a lot of what is been discussed here is redundant. If however you are a competitive athlete - Team sports, Powerlifting, Weightlifting, Strongman etc you are looking to improve your performance. Therefore you do not want to waste your finite energy systems and recovery ability on exercises that do not lead to an improved performance. How far you take this exercise is up to the individual. It would not be easy to interrogate every single movement in your training each week and clearly be able to correlate this with your chosen sports performance. You can however do this for your main lifts. Are you able to identify if you add 10kg to your squat for example, that it led to an improved vertical jump, or 20m sprint time? If you are keeping a log and show that when you improved that squat by 10kg your sprint time decreased by .25 seconds than you know that there has been god transfer from the squat to your sprint ability.
You invest a lot of your time and effort into training. Do not let it go to waste by doing things which do not lead to an increase in performance. Be analytical in the way you approach your training and think carefully about your approach. Seek out ways to measure transfer and keep a keen eye on this when designing your training. If you can't be certain that it is beneficial to your chosen sport, the question needs to be asked; "why am I doing this?".