Accessibility is often treated as a compliance checkbox. Built in from the start, it's actually a usability upgrade for every user.
Semantics first
Use the right element for the job — a <button> is focusable, keyboard-operable
and announced correctly for free. Reinventing it with a <div> throws all of
that away.
Keyboard is the baseline
If it works with a keyboard alone, it works for a huge range of assistive tech. During the OpFix accessibility pass, fixing keyboard traps and adding visible focus improved the experience for mouse users too.
Label everything
Every input, icon button and control needs an accessible name. Screen-reader users navigate by those names.
The lesson
WCAG isn't a ceiling to scrape under — it's a floor that makes your product better for everyone standing on it.