Accessibility improves design for everyone, regardless of anything about them.
I use the traditional way of web design, which lends itself to better accessibility for everyone.
I have continued to learn about web design for almost 25 years.
I am disabled myself and getting older. So I am preparing my website for when I (in addition to suffering from a mental illness) likely will have more physical limitations as well.
I think the website designer should optimize their site for the beginning user as the advanced users should be more able to figure things out, then the other way around.
I agree with the mantra - Do Not Make Me Think. This means that a user should not need to think to just browse a website. Unlike art, design is about how things work, not how they look, given they don’t look jarring. People only have so much emotional energy throughout the day and I do not want to be wasteful with this resource.