I think the more reliable information we can gather to assess training loads and evaluate training responses and adaptations, the more effective training can be. But only as long as we can deal with that information in a time-efficient manner and make sense of it. I always avoid collecting data unless I have the means to analyze it fast enough and interpret it in such a way that it becomes understandable and useful for the coaches. Otherwise, it is a waste of time and resources, and it undermines the credibility of a sport scientist. In my view, the coaching of athletes to prepare for competition will never be a total science and will always remain an art.
Mladen does a wonderful interview with one of the best Sport Scientists in Endurance. While his expertise is Tapering, I think he is just a great well rounded expert and his interview can be found here.