This is the point I was trying to make in my own debate about whether or not to get them. Like Rico said here, and also makes a point in Head Games, because people are different, you can't take a cookie cutter approach. Some people learn things differently, some have different skills or abilities. If you understand the concepts and principles of bowling in general, you can better coach each individual. If you get drawn into the idea that you have to teach something a certain way and a person has to learn something a certain way, yeah some people may get it, but many others may not.
I'm sure there's some applicable information in the USBC certs, but if you look at it, you have extreme basics with Bronze, slightly advanced things in Silver, and the only thing between you and getting Gold is a review of what you've learned. Most people getting these certifications wouldn't be getting them to learn, I imagine, they'd be getting them to beef up their resume. Like it or not, resumes matter to the average bowler or average customer. Again, whether or not it means something to a professional is one thing, but sometimes you have to have those feathers.
To answer the OP though, it really matters what the intent is I think. If you already feel you're competent at coaching, and aren't in it for the money, I doubt you need it. To coaches seeking to draw people to coach, a Gold level certification is a big plus on the resume, and whether it means they know what they're doing or not, or if they coach exactly the same as they did before they got it, people will automatically give them more credibility than someone who may be a much better coach. Sometimes you need those things to get your foot in the door.
Also, all good coaches are not necessarily great bowlers themselves. Their knowledge and eyes can see what needs improvement with someone they are coaching. That doesn't always translate to coaching themselves.
One last point.
It is goes to the college degree argument.
You are the hiring manager for a company.
On paper, 2 candidates look identical. Except 1 has a degree.
More often than not, the degree person gets the position, even though then non-degree person may actually know more. They just do not have that sheet of paper.
At what point does experience overcome the lack of a degree?