Learning Spanish will certainly enhance your skills if your career is in anthropology, development studies, law, teaching and other areas.
In all these areas Spanish as well as Latin American countries are active innovators and producers of knowledge. Let's take Development Studies for example. Since the very beginning of what today is known as Latin America, its populations base their doings in alternative ways of conceptualizing and understanding the "bien vivir" (close but not the same as "good life'), consequently their understanding of development is different than western extractive perspectives.
If you study Development Studies you will come to understand what is called "post-development" and "post-extractivism" as it is conceived in countries with other than western heritage. You will be able to expand your understanding of these concepts and will be able to see the limitations of global discourses on development.