Comment by petmon

Miners have real expenses: electricity, depreciation, etc. Miners also generarte revenue, $45 million per day is a reasonable estimate [1]. This revenue is extracted from the Bitcoin system through both transaction fees and inflation (creating new Bitcoins), but these are sold in portion to pay real expenses, with presumably some profit.

We can estimate 300k transactions per day, which implies about $150 revenue per transaction. Miner revenue is your cost: it is what they extract from the Bitcoin system.

One Bitcoin transaction costs on the order of $150. It's really expensive.

1: https://www.blockchain.com/charts/miners-revenue