..And what makes you think that it is a lack of ability to type correctly that has someone like me looking for a backlit keyboard?
Without needing to justify myself, because frankly, I don't need to, I happen to have a SO who is legally blind. And a backlit keyboard helps her out TREMENDOUSLY, much to the chagrin of your assumption that she could not type correctly.
One of the things that has endeared her to Apple products is their built-in functionality to help the disabled, whether visually or physically. And the more independence she has (read: not depending on someone else to help her unless needed), the better a person she is and more of an equal she is to normal-sighted people.
So until you know the reasons why someone needs a backlit keyboard, no matter how petty or important they may be, please keep the assumptions to yourself.
BL.