You can think of usability as research into a product or service to determine how intuitive, efficient and user friendly it is. This practice is used to build better tools to solve the world's greatest challenges, and to discover how we can bring technology to those who don't have it and could benefit most from it.
Equal access to information for all is a right, and it is the law of the land, put forth by the Americans with Disabilities Act. This means that, if you have a customer base that uses your service in almost any way, you may someday soon be required to ensure that all digital tools you offer are available and compliant with Digital Accessibility standards.
I believe that the future holds so many wonders, that technology has the potential to do great good, and to someday soon begin to level the playing field for those who have not yet fully benefitted from the power of the internet. I believe that as we open our technology to more people of varying abilities and skillsets, that we will discover new ways to share and experience it. Making technology more accessible and usable, then, is not simply about ADA or WCAG compliance, it's about uncovering the next big leap forward in innovation.
-Nielsen Norman Group