Not to downplay the pure and applied mathematics implications. But the immediate discovery was made in the context of calculating neutrino oscillation probabilities. Yielding insight into matter / anti-matter imbalance in the known universe ;)

Eigenvalues: the Rosetta Stone for Neutrino Oscillations in Matter

https://arxiv.org/abs/1907.02534

Deep Underground Neutrino Experiment

https://en.wikipedia.org/wiki/Deep_Underground_Neutrino_Expe...