But it does ultimately mean that we will use more and more electricity to produce - what? To produce tokens of value. But, to me, that electricity is completely wasted.
You got it backwards. The electricity is not used to mine bitcoins, but to make the system secure. Miners get a compensation in return for their trouble. Without bitcoin mining, it would be impossible to guarantee security.
These days everything can be hacked. However, the security comes in when you consider that all of these miners work hard to solve insanely complex mathematical problems. If you wanted to hack the system, you would have to single-handedly put nearly as much computing capacity as the rest of the world combined, which is unfeasible. That gives the security.
Also consider that banks, too, have to spend significant resources and money on security. How much fuel do you think armored cars consume, when they're super heavy, and they never turn the engine off? Huh! Security always costs money.