Metaphor , between semantic innovation and conceptual transfer

There is a common element to studies that in recent decades philosophers, psychologists and linguists have devoted to the question of metaphor: all point out that the metaphor is not simply a rhetorical device, a way to make the language more lively and attractive, but is instead a cognitive tool, a process that has to do with the thought as much and perhaps more than with language. However, just within these studies, we can find a singular oscillation. On the one hand, it is argued that the metaphor is pervasive in everyday life, namely that the metaphor structure how we perceive e how we think, allowing us to conceptualize the less tangibly or less clearly delineated in terms of the more tangibly or more clearly delineated. On the other hand, it is argued instead that metaphor produces an innovation both at the semantic as at the conceptual level, allowing us not only to extend or change the meaning of a term but also to reorganize the existing categories or create new categories ad hoc. This is a contradiction? Or the two theses are compatible with each other? These questions seem very relevant to a didactics of sciences who want to exploit the educational and communicative potentials of metaphor. In fact, if the metaphor involves innovation on the semantic and conceptual, as may facilitate the learning of complex concepts? Not quite likely to further complicate the learning process?