Interesting, I'm a phd-drop out in computational biology, working as a data science consultant: I use mathematics including multi-dimensional statistics, linear algebra, and calculus everyday. Being self-taught, I'm very self conscience about the math I don't know, but so far, not knowing differential equations doesn't seem to have hurt me. I actually just ran into a problem that uses Hamiltonian dynamics, so maybe I will end up learning differential equations, but it does seem like the course, as taught many places and in the Dover books I own, presents either no useful conceptual insight, like why I learned geometric algebra, or a powerful toolset, like some multi-dimensional statistics.