Universal (or broadened) accessibility means excellent usability, particularly for disabled people. But, argue advocates of assistive technology, universally accessible technology yield great rewards to the normal user; good accessible design is universal design, they say. The classic example of an assistive technology that has improved everyone's life is the "curb cuts" in the sidewalk at street crossings. While these curb cuts surely enable mobility impaired pedestrians to cross the street, they have also aided parents with carriages and strollers, shoppers with carts, travellers and workers with pull-type bags.
Consider an example of an assistive technology. The modern telephone is, except for the deaf, universally accessible. Combined with a visual feedback such as a calculator has, however, a deaf person can use a device like a telephone.
Another example: calculators are cheap, but a mobility-impaired person can have difficulty using them. Speech recognition software could recognize short commands and make use of calculators a little easier. People with mental disabilities would appreciate the simplicity; others would as well.