What are the odds that muons are more sensitive to neutrino interaction and this is what the scientists are seeing? Muons are pretty massive, after all, and neutrinos are literally everywhere. Obligatory: "billions of neutrinos pass through you every second".

Muons are leptons like neutrinos and their electron cousins, and we already know that electrons can be boosted by the occasional neutrino interaction. A free muon in a magnetic field has nowhere to be boosted to, so, coupled with a hypothetically higher chance of interacting with a neutrino, I'd expect something to happen when it does, though not exactly what.

I figure we don't already use muons in neutrino detectors because they don't last very long (about a second) before decaying, and the only way to get them to last longer is to accelerate them to a decent fraction of the speed of light. That way, from our reference frame they can last minutes or more. That's going to be energy-hungry compared to the passive detectors we have.

i.e. the passive detectors which take advantage of the aforementioned electron / atom interaction.