A diabetic is not required to wear special diabetic shoes but if someone is diabetic then the doctor will suggest that the diabetic wear the diabetic shoes and can prescribe the diabetic shoes to the diabetic.
When a person is diabetic they have badly controlled blood sugar and also poor circulation in their feet and by wearing the special diabetic shoes the diabetic will have better and improved circulation in their feet.
The diabetic can also suffer nerve damage and skin disease when they don't wear diabetic shoes and the diabetic shoes help to prevent further nerve damage and help manage and prevent further disease of the skin.
So it's really recommended that a diabetic wear special diabetic shoes at least some of the time to help manage the diabetes and help prevent further health issues.
My Grandma wears diabetic shoes sometimes but not always because she says they are not comfortable.
But as long as you wear the diabetic shoes at least sometimes you'll be okay although you are not required to wear the diabetic shoes as it's entirely up to you.