Hi Nicole:
For me, if a student wants to do something special and is not asking for extra credit, that's terrific. I think you're right in that the students will probably be more motivated in class. And there are methods other than points to recognize extra effort, besides points.
I think in most cases if there is information that is worthwhile, it ought to be included in the regular, required curriculum. Negatives such as grade inflation, fairness, subjectivity, and reqwarding marginal performance are among the cheif reasons I choose not to give extra credit.
Ultimately, each teacher and institution has to come up with their own rationale and policies regarding this controversial topic.
Regards, Barry