Won't the supply-side incentives misalign with demand-side's desires in this case?
If you choose a specific company's free tier, you can rely on reputation and switch if they misbehave (e.g. they exfiltrate your secrets, log all your activities, build a profile on your workload behavior, etc). But if you don't know where your workload being deployed, the operator has less incentive to treat your compute with respect.
Means this is really only useful for nearly-public workloads, where tampering is not a critical failure mode.
I think you misunderstand what ghost is. It's not a cloud service. It's a CLI tool that runs workflows from your GH account: https://news.ycombinator.com/item?id=47982915
The multi-provider angle is an interesting future direction. I built it atop Actions because that's what I use everyday, but I'm sure other similar things exist.
The main driver for me was I always felt actions had so much potential for a modicum of easier use, that would give huge benefits to my workflwos. Ghost CLI is that little bit easier.
That is why unless you own it yourself, a "free tier" is not truly "free".
This service uses GitHub Actions and it is likely against GitHub's terms of service and GitHub can pull the rug if they wanted to.
If you don't own it, there is always a catch when something claims to have a "free tier". This is one of them.
I think there's a case for self-hosted runners, and right now it only supports the basic ubuntu, macos and window latest. But I see a path to adding the larger paid runners as part of the toml for machine shape in future.