I'm reading an essay discussing the measurement of Higgs boson mass: https://cms.cern/news/cms-precisely-measures-mass-higgs-boson, which says that the latest and more accurate measurement results came from two procedures. One of them looked at decays to two Z bosons, which subsequently decay into electron or muon pairs, and the other focused on decays to two photons in the Figure below.
I also found similar graphs which feature other Higgs decay mechanisms, such as
I can see for both decays, the products are around 125 GeV, which is also the mass of the Higgs boson. My question is why don't experimentalists determine the mass through the second (or other) decay processes? What else information can we learn from the graphs like this?
Many thanks for the help!