Anecdotal evidence is important.
People's experiences are important. They matter.
Scientists don't know everything, they don't understand everything. The human immune system, for example, scientists don't fully understand it, it's far too complex. They understand bits of it, but that's all.
The human immune system is exquisite, it's evolved over hundreds of thousands of years. It knows exactly what to do to combat infections, and trauma and it keeps cancers at bay.
When you fall over, your immune system is preparing to heal you before you even hit the ground. That's frankly, amazing.
And of course it's different in every human body. Every human body reacts differently. So that's billions of different reactions. Scientists can't even begin to understand all those billions of different ways our bodies react.
That's why a "one size fits all" policy is never a good approach to health care, in fact it's unscientific and quackery. You interfere with the human immune system at your peril.