An accessibility overlay does not fix your website. It adds a script that layers a widget over the top of it, leaving the markup underneath exactly as it was. The barriers are still there. There is now a button that claims otherwise.
That is the short version. The long version is worth reading if you are being sold one.
What an overlay actually does
You add one line of JavaScript. On load, the script injects a floating button, usually a wheelchair icon in a corner. Clicking it opens a panel with toggles: bigger text, higher contrast, a dyslexia font, stop animations, a reading guide.
Some overlays also try to repair the page at run time, guessing at missing alt text and adding ARIA attributes.
Both halves have problems.
The toggle panel duplicates the browser
Every control in that panel already exists, built into the operating system and the browser, and works on every site rather than only on yours.
Someone who needs larger text has already set larger text. Someone who needs
reduced motion has already turned it on at the system level, and any site built
properly honours prefers-reduced-motion without being asked. A screen reader
user has a screen reader, which is vastly more capable than a widget.
The panel is a second, worse set of controls, available on one website.
The automatic repairs guess
This is the part that does damage.
An overlay cannot see your images, so generated alt text is a guess. A wrong description is worse than a missing one: a missing alt attribute tells a screen reader user that something is unlabelled and they can go and look for context. A confident, incorrect description tells them something false and gives them no reason to doubt it.
ARIA added by a script has the same problem. aria-label on the wrong element,
or a role that does not match the behaviour, makes a page harder to use than
leaving it alone. The first rule of ARIA is not to use ARIA when native HTML
would do, and a script applying it in bulk cannot make that judgement.
Why disabled users object
This is not a theoretical objection from developers. It comes from the people overlays claim to serve.
Hundreds of accessibility practitioners and disabled users have signed public statements against overlay products. The common complaints are consistent: overlays interfere with the assistive technology people already use, their automated fixes introduce new errors, and their presence is used by site owners as a reason not to do the actual work.
That last point is the real harm. An overlay is frequently bought precisely so that nothing else has to change.
The legal position
Overlay vendors market compliance. Several have faced regulatory action and litigation over those claims, and websites using overlays have continued to receive accessibility complaints and lawsuits.
That is the obvious outcome. Regulations are about whether your site is usable, not about whether you bought something. A widget that leaves the underlying barriers in place leaves you exactly as exposed as you were, with an added paper trail showing you were told about the problem and installed a badge.
What to do instead
Fix the page. It is less dramatic and it actually works.
Find what is broken. Run a real audit against the rendered page. Automated checks will settle a meaningful portion of it — missing alt attributes, unnamed buttons, skipped heading levels, contrast failures, targets that are too small.
Fix it in your own code. A change to your markup or your own stylesheet keeps working when you change plugins, keeps working for everyone, and does not depend on a third-party script loading.
Do the part machines cannot. Tab through the site. Try it with a screen reader. Those two exercises will teach you more than any report.
Write down what you did. An accessibility statement that names known problems and says when you will deal with them is more credible, and more useful, than a badge claiming perfection.
How this plugin approaches it
WOWStudio Accessibility Remediation was built around that position. It scans your pages, shows every issue on a live preview of the real page, and proposes changes to your own markup that you review before anything is applied.
Nothing is added to your front end for visitors. No script, no widget, no badge. Markup changes live in a reversible layer so your content is never overwritten, and style corrections are written into your own Additional CSS, where you can read and edit them without the plugin installed.
It also refuses to generate alt text, for the reason above. Where a correct answer depends on what your content means, it tells you so and gives you the fastest way to write it yourself.
Questions people ask
Are overlays ever useful?
The toggle panel is redundant rather than harmful on a site that is already accessible. But a site that is already accessible has no reason to add one, and a site that is not is not helped by it.
What if my overlay vendor offers an audit too?
Then take the audit and skip the widget. The audit is the part with value.
Is an overlay better than doing nothing?
No, for two reasons. It can introduce errors that were not there before, and it reliably delays the real work by making the problem look solved.
If you want to see what is actually wrong with your site, the plugin is free on the WordPress.org directory, and the documentation explains every check it runs, including what it cannot catch.