Can you provide a summary of Satoshi’s argument here? I’m failing to see how the usage of electricity, which is an entropy-losing process, leads to added value through bitcoin

I think I understand Bitcoin well enough to detect that you don't know what you're talking about.

One could argue that a higher current difficulty increases trust in very recent transactions, thereby raising the unitility of Bitcoin as a medium of exchange (ha!) and thus affecting the price.

But that effect is small and we're talking about the difficulty during the last 10 blocks, at most.

Anything before that is for the past.