It has to be "crippled" in some way. I would term it as modified .
Market differentiation/segmentation. The (newer) Celerons (as with the older Coppermine Celeries) cannot in any way impede the potential sales of its more expensive brethren, the P4 (or the older P3).
(Intel) learned from their lesson from iP2-450/iC-300A->450 experience.