A model is generally not intended for execution but rather for implementation. There is a definite difference between a model and a process, which is normally expected to be executable. A process is a special type of model. Model is more generic term than process.
It is incorrect to think that BPM deals exclusively with processes. Processes comprise an important part of business process modeling (BPM). However, BPM is much wider than just process modeling alone. Non-executable models are essential part of BPM.
As most evident example, organizational diagrams are not executable and are not processes. More generally, every EA diagram and enterprise architecture in general is a structural rather than executable field. There are a lot of BPM tools, which focus primarily architecture and modeling aspects, rather than execution. This modeling is equally or more important than execution as such.
It is often observed unjustified bias towards executable models in BPM. Such an approach substantially undermines generic appeal and significance of BPM neglecting EA, MDM and many more purely modeling aspects. Ideal BPM implementation should achieve harmony in its modeling and execution dimensions.