The question in your title is very good. Yes, it is true strength for health, well-being, happiness, and productivity. A few years ago I wrote a case study about it featuring a 103 years medical doctor who owns her longevity to letting go. I link the story here as a reference. https://medium.com/sensible-biohacking-transhumanism/the-surprising-links-between-letting-go-and-a-long-life-42ab5476ce4d

You inspired me to write a follow up piece by sharing my personal experiences.