My understanding is that most of these "just as a script" type tools are of minimal value to people with real disabilities. Most of the options they offer are a

My understanding is that most of these "just as a script" type tools are of minimal value to people with real disabilities. Most of the options they offer are already available as browser settings or external tools in the first place, and any additional support could be more effectively done by just making the right choices in the first place: proper accessibility tags on things like images and icons, text over iconography (or better yet text with iconography), proper semantic markup, etc. For more complicated things you need to start working more with aria tags, but in my experience they're a lot less complicated than they seem. And in card where interaction is involved (e.g. drop-down search bars) are usually better handled by either the browser, or an external library that will also handle the accessibility aspects. (This is true for pretty much all users - I use a lot of websites where their custom widgets are really hard to navigate if I'm using the keyboard. Doing this properly benefits pretty much everyone.) The other way of thinking about it is this: if these drop-in scripts were sufficient, why aren't people with disabilities using them via some sort of browser extension, thus negating any need for the law in the first place? After all, if it works so well, people with disabilities should have no issues browsing any site on their own... In practice, these scripts tend to oversell their benefits and be targeted at able-bodied people who don't have as good an idea of the full set of needs (and tools) that people with different disabilities have.