Razor is for private cloud, the biggest problems it solves are bare-metal provisioning as well as OS-specific mass-install tools. One of use-case for Razor: pop-in a new server into the rack, get provision ESXi with Razor and then provision a number of CentOS and Debian VMs without having to care how different is Kickstart from Preseed. It's a great too, but it's mostly for private cloud and Teraform is for public cloud and is therefore at a higher level.