Several experimental collaborations have recently invested considerable effort in precision studies of hadronic tau decays. With further improvements expected at Belle-II, it is timely to discuss the theoretical implications of these experimental advances.
In this talk, I will review several such implications. First, it will be shown that hadronic tau decays represent a clean laboratory for the precise study of Quantum Chromodynamics (QCD),
allowing in particular for an accurate determination of the strong coupling constant alpha_s. Second, these decays can be used as a probe of the electroweak interaction. In this respect, I will discuss the extraction of the CKM matrix element |V_{us}|. Finally, I will review the status of the Standard Model prediction of the anomalous magnetic moment of the muon and how hadronic tau decay data could affect it.