By writing for an application server that is not branded J2EE compatible, I could be writing to a proprietary implementation, thereby locking my application and my code into a vendor-specific, nonstandard implementation. When my business needs change and I need a different application server, the development team will have to spend additional time and resources to modify what they have already written. This means substantial additional costs and is too high a price to pay.
Portability is important to me and the reason for my purchase of a J2EE application server. Your implementation of the J2EE specification, however, has not been tested in accordance with the Compatibility Test Suite and therefore cannot provide the assurance that the J2EE compatible logo delivers of lowering development costs by eliminating vendor lock.