At least one game (Super Mario 3D Land) have BCMDLs that have no animations of their own, but they use animations from BCMDL files that don't contain models.
You can load the model file, and then use the import button in each of the animation tabs on the right. Select the animation bcmdl and it will import them.
At least one game (Super Mario 3D Land) have BCMDLs that have no animations of their own, but they use animations from BCMDL files that don't contain models.