Hi Barbara:
Although there probably instances where some form of bonus point (say, on a final exam), or in certain classes where the the students creativity is being assessed, I agree and do not use EC. If it's important enough to be graded, it should included in the total course points and so stated at the beginning of the course - not as EC but as required credit for required assigned. Graing is according to performance.
Many teachers and institutions have polices that flatly do not permit EC; I am in that camp.
Regards, Barry