No. Creating and benchmarking individual buildings is optional. You don't have to add individual buildings unless you would like to track their performance separately, and this is only possible if your buildings are separately metered. If your buildings are not metered separately, it's probably not worth entering them individually.
Meters entered for individual buildings can be associated to the individual building AND to the parent property so you don't have to create and maintain duplicate meters at the building and property levels. [See related FAQ about how to set up your meters.]
If your property is NOT a Hotel, Multifamily, Senior Care Center, Hospital or K-12 School, only your individual buildings will be eligible for the ENERGY STAR Score. It's best to meter and benchmark individual buildings in these cases.