Also, it's not just your site. It's every site. And the customer pays all those millionths of a penny added up out of their pocket. And all those 5 second delays out of their lifetime.
Edit: btw at a quick glance you underestimated cell phone soc TDP by a 2-4 factor.
A single use of an electric kettle sounds like it would completely dominate this consumption.
The time cost is certainly the greatest expense here, power is cheap in consumer computing contexts, generally speaking (at least nowadays with most things racing to sleep), and is mostly relevant because of battery life, not power cost.
Also, it's not just your site. It's every site. And the customer pays all those millionths of a penny added up out of their pocket. And all those 5 second delays out of their lifetime.
Edit: btw at a quick glance you underestimated cell phone soc TDP by a 2-4 factor.