Why should I trust a corporation (e.g. Valve) with 2-factor authentication?

Formerly, posting your real name online was a cardinal sin, and providing a service with a phone number wasn't much better. If the odds of my account being compromised without 2-factor authentication are low enough, what benefit is there? It seems both inconvenient, and invasive. I have no reason to trust a company.

I don't feel the need to connect my internet accounts with myself. An email (even a temporary one) and a password should be good enough, and I'm very grateful that some services (e.g. HN, reddit) still follow this model.

I assume some of you aren't on the same page, and I'd like to know why you consider it beneficial.