Some people have other issues like diverticulitis that need to be scoped. I followed my diet strictly for years, yet ended up in 2010 with a perforated bowel. Needed an emergency colostomy, that they reversed three months later. It wasn't a pleasant experience, and I wouldn't wish it on my worst enemy.
Well, okay...maybe I'd wish it on Nancy Pelosi.
I get that. I’ll use me as an example. Never had an issue with intestines. I get the cheapo colguard and will get the full colonoscopy if the test finds a cancer.
For those as you state that have issues a colonoscopy is a very wise choice.
As for Pelosi she can go drink magnesium citrate and habaneros and have fun. That lady is one evil woman.