While many professions require being on a computer all day, writers have a specific set of needs.
Because they type all day, every day, their keyboards need to be particularly functional, comfortable, and ergonomic, to avoid repetitive injury over time.
A good keyboard should help to support you in becoming a better, faster, and more focused writer.
Since no two writers are the same, you should also be choosing a keyboard that fits with your writing goals and lifestyle.