Vector algebra is often seen as a staple of applied geometry. Vector products have so much to do with angles, projections, areas, and volumes that it’s hard to imagine doing anything practical without them. Vector algebra is also a never-ending source of interview problems.
In practice, however, vector operations are usually concealed under utility functions’ interfaces to such a degree that about half of candidates who apply for a job in my department can’t tell the dot product from the cross product. These people are still doing fine professionally. But without regular practice, the math behind the interfaces fades from memory.
In the modern world, vector algebra isn’t so much a must-have as it is a powerful enabler. It enables you to go beyond the utility functions your framework gives you. It enables you to write your own utility functions tailored to your own specific tasks, as well as highly efficient code that doesn’t rely on utility functions at all.