Based on my experience I really do think most people are using it for things that they could perfectly well do locally with far less complication.

Perhaps that isn't most use of it; the big projects are really big.

Care to provide examples?

Fundamentally, yes, what you run in a CI pipeline can run locally.

That's doesn't mean it should.

Because if we follow this line of thought, then datacenters are useless. Most people could perfectly host their services locally.

> Because if we follow this line of thought, then datacenters are useless. Most people could perfectly host their services locally.

There are a rather lot of people who do argue that? Like, I actually agree that non-local CI is useful, but this is a poor argument for it.

I'm aware of people arguing for self-hosting some services for personal use.

I'm not aware of people arguing for self-hosting team or enterprise services.

Well, they are. Selling the team or enterprise a license to do just that is a rather large part of many businesses.