The most important thing to recognize about boxing statistics is that they have no real meaning apart from their context. And given the nature of professional prize fighting, putting them into proper context can be challenging, and a potential source of debate.
It is useful to compare to the situation in baseball, the most statistic-driven sport of all. A position player in baseball makes several offensive attempts everyday, over the course of months. They compete in a formalized league, where everybody competes against everybody else.
So baseball stats are drawn from a large sample-size, gathered in a relatively controlled and consistent environment. For this reason, they can have genuine predictive value.
A world class professional prize fighter competes a few times a year, and while Major League Baseball hitters are compiling statistics against basically the same pool of pitchers, professional boxers often compile their records and stats against entirely different opponents.
There are plenty of fighters who run their professional records up to 30-0 or better, but don't truly have the same talent as a guy like Gabriel Rosado, with a record of 21-7. But if you didn't know a little bit about the sport, and about Rosado's history and who he has fought already, you would never know that.
In boxing, only the action in the ring tells the real story. Still, statistics can add a layer of analytic complexity that has value, if used properly.