Yes, buying it from the Vault gets you a Steam code.
Taken from the
Vault page:
- Comes as a DRM free download and with a Steam key.
So if they're giving out Steam Keys, are they still making more money off of a sale through the Vault than through Steam?
And if that's the case, why is there an option (for kickstarter backers) to select a copy of Original Sin through the Vault OR Steam?