Yeah, I see what you mean. In my case it is because I use LaTeX to create my resume, and my main concern is just that in some ATS systems it doesn't parse correctly and it would be nice to know when I'm making the resume, rather than when I apply for the job. For people without an existing opinionated workflow (likely the bulk), the resume scanner would be a good way to help them understand the value proposition of a unified builder that works with most ATS systems by design, rather than as an afterthought (which seems to be the case with most resume builders online besides this one).