There is a legitimate reason for people to mine until the end of the world thoguh and pay a little overhead compared to buying already-existing BTC:

Mining is a way to create completely new, fresh BTC with zero history.
Coins that have never moved on the blockchain, have no history and can't be traced to any exchange or other wallet.

No tax authority, third party, investigator can ever know who owns these freshly minted BTC with any amount of effort.

What kind of people need these is up for speculation, but they exist.