Testimonial evidence exists for pretty much any claim that has ever been devised — alien abductions, demon possessions, miracle medical cures and the like.
One needs to look no further than the dietary supplement industry to see the influence of testimonials. In fact, testimonials are probably the key marketing tool for the supplement industry. Medicine, psychology, and the beauty industry, to name a few, often refer to testimonials in an effort to show the efficacy of their products or treatments. It is not uncommon for people to make decisions based on testimonials that conflict with scientific evidence — giving more weight to the testimonial.
This is a mistake because testimonials are not real evidence.