I would bet good money, statistically, that forcing hand written tests with pen and paper is much more likely to disadvantage students with a medically documented physical disability than you are to encounter someone who can't type at all on a standard 101 key qwerty layout keyboard.
At my university, students with verified disabilities are allowed to use a university-provided laptop (properly locked-down, with allowed tools such as screen readers). But these are special cases. Computers for everyone would be costly and impractical given exams are punctual but all roughly over the same week or so.