I'm curious about them but I'm skeptical on their usefulness compared to existing things that can actual be observed with the naked eye. I'm a big fan of trouble shooting with an ohm meter and I could apply the same to a techniques to a visible light optical circuit.
What tools are used to trouble shoots a qubit?
What you are measuring with an ohm meter is not visible to the naked eye. Electricity is not visible to the naked eye. Neither is heat. Neither are x-rays. Neither is math. Their effects might be, but they themselves aren't.
It's easy to come up with more examples of things not visible to the naked eye which are very useful.
Observing the phenomena whether directly or indirectly we built a sophisticated society. I want to know how hard it is to observe a qubit. The directness is what I want.
What indirect effects of a qubit can one observe with the naked eye?