The strength comes from your hands, not your fingers, and unlike "real" massage tools, they are both hard and soft at the same time. A move that would wear out your fingers in a few minutes can be sustained for much longer when the strength comes from your hand/forearm.
I was able to heal someone of pain they had for a few weeks using one.
I also highly recommend this book for anyone with chronic pain.
The Trigger Point Therapy Workbook: Your Self-Treatment Guide for Pain Relief, Second Edition, by Clair Davies.
Very often the source of the pain can be inches or even over a foot away from where you feel the pain. When you find it, a dull ache will spread from the trigger spot. Basically a part of your muscle is not as limber as it should be and you feel pain at the attachment points far from that spot-- tho in some cases due to nerve pathways, where you feel the pain isn't even close to the muscle in distress. The book shows where the trigger points are likely to be when you feel pain in a given area.
I was trying to think of some sex post after posting in the other thread that there wasn't much discussion of sex in RSP compared to the R & P.
Best I could do that didn't seem like it had been discussed to death or wasn't a cliche or just too pervy to discuss in an open forum.