Hey Casey, this is one of the areas where things get a little weird because the W3 doesn’t actually have any say over the ADA guidelines, it is more than the ADA guidelines adopted the WCAG 2.0 guidelines as just that, a guideline to help. As far as I know, the tool you’ve linked to hasn’t been used in any judgements I’m aware of. Usually when it comes down to making a decision on if something is/isn’t compliant they have people use the actual PAWS tools and show what elements do/don’t work as intended or are otherwise inaccessible. Hope this helps!
Title II prohibits disability discrimination by all public entities at the local level, e.g., school district, municipal, city, or county, and at state level. Public entities must comply with Title II regulations by the U.S. Department of Justice. These regulations cover access to all programs and services offered by the entity. Access includes physical access described in the ADA Standards for Accessible Design and programmatic access that might be obstructed by discriminatory policies or procedures of the entity.
State and local governments will often post documents on their websites using Portable Document Format (PDF). But PDF documents, or those in other image based formats, are often not accessible to blind people who use screen readers and people with low vision who use text enlargement programs or different color and font settings to read computer displays.

You may have installed a ramp, increased the width of your door frames, or made other accommodations to ensure that your physical premises are accessible to all. The requirement for equal access used to only apply to physical locations and storefronts, but now the government is actively ensuring that the requirements for ADA accessibility include online properties such as websites and mobile apps.

Because they only read text, screen readers and refreshable Braille displays cannot interpret photographs, charts, color-coded information, or other graphic elements on a webpage. For this reason, a photograph of a mayor on a city’s website is inaccessible to people who use these assistive technologies, and a blind person visiting the website would be unable to tell if the image is a photo, a logo, a map, a chart, artwork, a link to another page, or even a blank page.

The Department has assembled an official online version of the 2010 Standards to bring together the information in one easy-to-access location.  It provides the scoping and technical requirements for new construction and alterations resulting from the adoption of revised 2010 Standards in the final rules for Title II (28 CFR part 35) and Title III (28 CFR part 36).