I'm a neuromuscular therapist for 21yrs now, doing the deep tissue work on quite a few athletes, including cupping and scraping if needed.
I strongly disagree, and know that it certainly does add to the final package. Breaking up scar tissue, areas of limited range of motion, creating separation... so many benefits. Bringing in blood flow helps with growth and repair. Improving mobility allows for proper posing and injury prevention.
I often take before and after pics, with noticeable improvements in posture, how someone feels, and the insane pumps in the gym afterwards.
Many discredit, because there are many practitioners who are ineffective. Poor technical ability and knowledge, not used to working with athletes, etc. But, can make a huge difference, when performed correctly and specifically