One's answer to this question depends on one's approach to Jewish Studies overall. If one conceives of the field as synonymous with the study of traditional Judaism, with a focus on certain canonical texts (e.g., Tanakh, Talmud), then language study would be necessary only insofar as it enables the reading and interpretation of such texts.
But if one adopts a more expansive view of Jewish Studies, one that has at its heart a process of critical reflection on matters of identity and culture formation, then it is possible to grant language study a role that is more than ancillary. Since language, by nature, encodes culture, the study of language can serve as one of the many sites for this critical cultural reflection. Such a view would imply a broadening of the languages in the curriculum, beyond the traditional focus on Hebrew, to include other languages with cultural significance for Jews throughout history (e.g., Yiddish, Ladino). More importantly, the teaching of these languages would not be restricted to grammar instruction, but would give attention to the interaction between the shape of these languages and the social and historical circumstances of their use.
In a Classical Hebrew course that I developed for the Jewish Studies program at UNC–Chapel Hill, we adopt just such an approach. In addition to presenting the fundamentals of Biblical Hebrew grammar, we explore the historical circumstances behind the emergence of Hebrew as a distinct linguistic entity in the southern Levant in the first millennium BCE. In surveying such topics as the invention of the alphabet, the pre-exilic inscriptions, and the development of the ancient Hebrew and Aramaic scripts, we come to understand the early history of written Hebrew in relation to the crafting of social and political identities. Thus the study of the language, beyond facilitating the reading of canonical texts, becomes also a window into the dynamics of cultural formation.