Looking at a sample set of "Errors" (
http://demo.pa11y.org/52457e2b135a4b51b4000001 ), it would be interesting to be able to get "Why do this matter to users?" information.
It may be obvious to a seasoned accessibility expert why things like "This text input element does not have a name available to an accessibility API", "Anchor element found with no link content and no name and/or ID attribute", or "Label found without a "for" attribute, and therefore not explicitly associated with a form control." are problems.
But I would feel a particularly strong imperative to fix these problems if, somewhere, I could see user-impact text. For example, "Some users will be unable to enter text here." "Some users will be unable to click on this." "Some users will not see this text when filling in a form."