The idea is that properties, for example, in the Bibframe vocabulary be underspecified – meaning many do not have defined domains and ranges – and that Bibframe Profiles provide a way to add specifics. We foresee Bibframe Profiles being used differently depending on which community is using Bibframe (and even within communities).
For example, the RDA community (libraries) may define a Work differently than CCO users (museums). A CCO profile that anticipates a sculpture might specify the use of the bf:dimensions property with a bf:Work. If thinking purely of literature printed in book form, one would assume the bf:dimensions property would go with an Instance (the material embodiment of the Work, i.e. the bound volume), but such a data point can be inherent to the conceptual idea behind an artwork. A colossal marble sculpture is, at a conceptual level, very different from a small bronze. [Caveat: Although I hope this RDA/CCO example is illustrative, my using “bf:dimensions” is not the best choice because it is currently defined with a domain of bf:Instance in the vocabulary. Alas.]
Does this help?