Why would I spend CPU time doing useless work in order to give them strange coins that aren't money when i could just save the money and give it to them directly?
in practice though I think it is not
In practice it's even worse. There's not a sane company in the world that would let some random bitcoin miner run on the same host as their mission critical system anyway.
[1]: https://news.bitcoin.com/bitcoin-accepted-tax-swiss-canton-z...
2. Most people won’t give them money directly.
3. It’s their choice how to monetize their project. It’s your choice to use or not use their project.