The primary reason to care about configurability, which is a dimension of overall usability, is cost. Difficult-to-configure systems
A related reason to make configuration easy is based on the architectural nature of the systems you're creating, which are increasingly built using modular approaches. Modular systems increase configuration requirementsa fact that becomes increasingly true in architectures based on Web services. Without a strong commitment to easy configuration, you're going to see configuration costs increase over the life of your application. This is not a pleasant prospect.
You must architect ease of configuration. Doing so is in everyone's best interest. In terms of usability, configurability is having the right number of configuration parametersnot too many and not too fewand choosing parameters that affect the system in ways that are material to the user .