Disability is not only about your current situation. It is also about future implications of future adverse events.
Disability is a safety margin: if you have a recognized disability, it means that you may be fully functional, but you are closer to being partially functional. Losing hear capabilities from one ear is not a big problem, unless I have already one functioning ear only.
Hiring you in the "people with disability" quota is a safety measure for your employer, too: if you have an accident and you require extended time out of work, they are covered by special agreements with insurer/welfare system.