I remain a skeptic but resist any hypocritical criticism until after I've tried one (or more) "professional" fittings. I endlessly tweak and tinker with positions of seat and pedals and handlebars and bike geometry --trying to figure out things. I have had reasonable success getting comfortable while also feeling I could be more aggressive.
But I keep thinking about various fads I've seen in the golf industry on club design (loft, lie, swing weight, grip, shaft flex, much more) and fitting systems that supposedly "proved" their new methods and techniques "scientifically." Most fall out of favor eventually. I might contend that everyone is different in what they want to accomplish and how their body adapts to what they are trying to do. I remain a fan of tinkering with the dynamics yourself and figuring out what works best for you.
I have to agree with this^, Even after the professional fitting, l felt like tweeking here and there to make improvements for comfort and it goes on and on for a while till you are reasonably comfortable and that alone seems to negate the setup. I wouldn't call it a fad but maybe just a good starting point. It definitely has value for some people.