the calculations make sure the btc network works.
so it can't be useless. or do you dismiss ALL of btc as useless?
The Bitcoin network is literally designed to incentivize, with payment, bringing new energy-inefficient operations online to “mine”.
The efficiency of the network gets worse and worse all the time, all while processing the same limited number of transactions.
Worse yet, Bitcoiners seem to like it this way. Proposals to increase block size have not been welcomed, and they go to great lengths to discourage switching to other protocols with better energy efficiency (because it would harm their investment).
The entire system revolves around inefficiency, and unfortunately we pay for that inefficiency with energy consumption.
That's exactly why the Bitcoin Cash fork happened.