>>16708024 (OP)Depends on what you want to study. Itโs particularly useful for algebraic topology and algebraic geometry. It also lets you quickly generalize many concepts. For example, a group action on a set immediately generalizes to a group action on any category if one just interprets a group as a groupoid with one object so that group action on an object in a category is just a functor. You can then quickly interpret what exactly is a free or transitive action is, on, say a manifold. You can then quickly generalize this to monoid and groupoid actions. So a vector space is an abelian group with a monoid action on it, which lets you quickly interpret why, for example, operator norms on Banach spaces are defined the way they are. Very nice way to organizing information and seeing why some structures in math behave โwilderโ than others.