As another commenter said, you're adding wear and tear to your own device. Sure, I have my own computers, but they're all spoken for, hosting VMs and containers or acting as my lab. Why should I subsidize the profits of a multi-million-dollar, for-profit company by letting them use my computer at no extra cost?
Your e-waste point is a good one, but I don't think Canonical's managers were looking out for mother nature when they made that choice.