Quantum computing could be defined as the art of harvesting quantum weirdness for computational purposes. But as computer science is about a little more than computers, this definition is not fully adequate and thus only provides an incomplete answer to the question: Why are we doing quantum computer science? This talk aims to provide a hopefully more accurate depiction of the field and its stakes. I will succinctly present the basics of quantum computer science and roughly sketch the landscape of its different subfields. Then, I’ll present various motivations for studying quantum mechanics’ computational aspects based on my experience and my work on the ZX-calculus. I will argue that quantum computing is a relevant addition to computer science beyond the technological challenge of building and exploiting a quantum computer.