One of my homes in San Francisco was a nice, sunny little studio. On one warm day, some ants crawled up through the wall from the trash cans a story below, and searched my apartment for food. Gross.
Seeing a line of ants crawling turned my stomach. I took a paper towel, wiped them up, and threw it out. A dozen or so crawled up my arm in the process. I washed them off under a faucet.
But they were tenacious. It took a lot of water to get them off. Gallons, just to drown a few ants. First thought: “This is not efficient.” Next thought: “Maybe that’s just how much water it takes.”
This is the concept of overkill.
It only takes a drop of water to wash an ant down the drain. But not every drop of water will knock the ant off its perch. Only 1 in a million drops will. To ensure success, you pour a million drops. All the drops up until the kill shot are overkill. But overkill is not waste. “Waste” implies there’s a more efficient alternative. Overkill is more like insurance.
If you go a month without needing to see the doctor (hopefully most months), is your health insurance premium a waste? No. The premiums you pay are “overkill”, but they ensure you’re covered when you need it.
When people call bitcoin mining a waste of energy, the same concept applies. In bitcoin mining, computers solve a math problem through brute force—trying many options until they find one that works. All the failed attempts are overkill, but necessary to get that single, correct solution.
Overkill is not waste. It’s only waste when you have a more-efficient method to achieve the same end.