It reads your text, not your audience. Two bios can score identically and convert completely differently because one of them names a thing its viewers actually want. No rubric can see that from 80 characters, and this one does not pretend to. Use the score to remove the mechanical failures, then test the wording against your own profile traffic.
The topic and role detection works from a fixed vocabulary of common niches and jobs. It will miss a niche it has never heard of, and when it does the tool says it detected none, keeps the placeholder in the templates and asks you to fill it in. That is deliberate: inventing a niche from one ambiguous word would put a claim in your bio that you never made.
It has no opinion on whether your bio is true. It can tell you that a concrete number would strengthen the line. It cannot tell you that the number you put there is real, and neither can the people reading it, which is a good reason to only use ones that are.