And if the marker chips in your "some unknown usb cable" are fake / counterfeit ? Then what ?
Your $40 toy won't help with that scenario and you will be back at square one. That's what.
Maybe you need absolutely 100% confidence your labels don't lie, but I and presumably others on this thread merely want to check for the presence of the label and the declarations on it. That's enough for me to sort my cables.
Maybe occasionally I'll come across a counterfeit cable (or more likely, a damaged cable, because I generally buy reputable ones) and have one underperform its label, but I can get rid of it then.