That's completely besides the point. The point is that people (the so called miners) spend a ton of electricity only to get a number. Electricity is a valuable resource people can live off of. While a number is not. Numbers are worthless. Currently people buy these numbers blindly, because they are driven by greed, so miners are able to sell them. But what will happen when things turn around?
Regarding fiat currencies. You are ignoring the fact that fiat currency units are just an evidence in the process where borrowers borrow and return goods, services and labour(valuable things). In bitcoin system these things are not borrowed and returned but given for free(for worthless numbers). After people did that, they have faith someone will give them the equivalence of valuable things as well. Bitcoin is simply an evidence of people who live in this faith.
lets word things in your language. maybe you will see the point then
people (so called employees) spend a ton of muscle energy only to get a serial number. energy is a valuable resource people can live off
people (so called goldsmiths) spend a ton of fuel only to get a bunch of atoms. energy is a valuable resource people can live off
now lets repeat your example
people (the so called miners) spend a ton of electricity only to get a number. Electricity is a valuable resource people can live off of
regarding bitcoin
you are ignoring the fact that bitcoin is just evidence of complex mining where acquirers use valuable things(electricity). in fiat, bank notes are not created at a cost, they are evidence of 0cost creation..
in fiat these things are not mined, but given for free. after people get that, they have to give it back at extra cost to themselves so banks can profit. banks work on faith that people will pay back more for something that cost nothing