Does a website accessible to people with disabilities benefit from a SEO bonus?
Web accessibility is a complicated subject and does not only concern blind people. There are many forms of disabilities (motor, cognitive, technical…) and it is perfectly possible to create a website with accessibility problems. Actually, most websites suffer from this kind of problems because of the lack of expertise in this field.
However, when you consult the web accessibility standards, you can only notice that a significant number of recommendations are common to the SEOs recommendations.
Criteria such as alt attribute information in illustrations are useful for both engines and text-to-speech users.
It is common to hear SEOs say that Google is the first disabled visitor in the sense that their robots have neither eyes to see your site, nor hands to click, nor ears to hear.
It is definitely a shame to take an interest in Web Accessibility in order to SEO optimize but if SEO can help to promote the development of accessible websites, we can only be happy about it.
There is no bonus for web accessibility. Getting a certification, badge or validation will not grant a bonus. However, it is perfectly possible that such an approach would allow you to correct SEO problems.