This has many benefits: for one, if you could read the input settings, in-game tutorials would be far better. Right now you have to use awkwardness like "press whatever key you have set to the fire button", or else go through the pain of making your own input manager just for this purpose.
Or in those cases where you don't have the built-in input manager and have to write your own anyway (web players, widgets), having access to input settings would allow the continued use of GetAxis and GetButton while being able to allow players to set keys, instead of having to use the less-than-ideal GetKey.
Also, you could change input settings on the fly, instead of (for example) having to create two axis setups using the same keys when you want the controls to behave in two different ways. This is especially awkward because then players have to set the controls twice in the input manager.