You're right. I was thinking about it wrongly for a second there. I would be really surprised if daily fluctuations mattered even after controlling for week fixed effects. I should probably try it, but if that were to happen I'd probably think it was bot related.

This is why it's so tricky. If zapping actually leads to positive ROI denominated in sats, then higher bitcoin price should incentivize more zapping, not less. I do think there's some variation to be exploited regarding the return function between reward amount and zap amount.

Another tricky thing about this is that the reward system has changed multiple times throughout SN's life, which means I'd have to try and back out those periods.