Mirror neuron mythos is ridiculous. They're just normal neurons, they just happen to fire in response to externally observed behaviour as well as personal behaviour.

They aren't magic, they can't actually mirror what's going on in another person's head or give you a high-resolution idea of how their brain works. They aren't even that good at mimicry unless you already have a pretty high-resolution understanding of what you're trying to improve. You can't learn to juggle by watching people juggle. You can't learn to play piano by watching people play piano. You might be able to improve those skills if you already have them and watch someone who's better, but it's limited and whether that's even osmotic mirror neuron activity is controversial.