Atomic physicists are forever excited about studying both ultracold matter and the techniques to produce it. I will attempt to explain the reason for this excitement by answering the title question. We will see that this march towards absolute zero is spurred on by the desire to control the Boltzmann factor and gain full quantum control over matter.
Following this introduction, I will focus on our own work producing ultracold matter in a new form (molecular ions), as well as some interesting detours in quantum chemistry and non-equilibrium physics that we took along the way.
I will conclude by doubling back and asking: are there other ways to beat Boltzmann? Excitingly, a certain isotope of thorium may hold the key and we are zeroing in on it.