Scrum vs Waterfall
Scrum is a framework, Waterfall is a model.
Can they be compare according to this definition?
Most likely, but how useful is it to do so? Perhaps you should say one is a framework for empirically managing complexity, while the other is a model for handling certainty.
I wouldn't compare frameworks to models. Frameworks are a level of detail lower than a model.
Scrum fits into the evolutionary delivery model. It can be useful to compare the evolutionary delivery model with the waterfall model to understand pros, cons, risks, and benefits. However, even within the methodologies that fit into the evolutionary delivery model, Scrum contains a number of practices, such as timeboxed development, cross-functional teams, that may or may not be found in other evolutionary delivery models.
Should we use Waterfall or Agile? Many organisations face this decisions many times. Most are more experienced at Waterfall than Agile. Comparing Scrum to Waterfall is invaluable as it communicates the differences that people should expect. It also hopefully enables those dedicated to waterfall to at least consider some of the aspects of Scrum which can be used to their advantage.