I just spoke to a Crystal reservations agent who also said that onboard credit cannot be used for excursions and cannot be used in the shops onboard. He said onboard credit can only be used for the spa, premium liquor/drinks beyond what is already included in the cruise, and specialty dining beyond what is already complimentary.
This makes no sense. You all agree and have experience that onboard credit can be used for all of the above items including excursions and in the shops on board?