What are the cons instead of using Ansible (or others), just do simple clone of virtual disk image from some configured master? There will be still need to conf

What are the cons instead of using Ansible (or others), just do simple clone of virtual disk image from some configured master? There will be still need to configure some things (IP addresses,...), but lot of things can be shared. Also one can use LayerFS to have shared things in RO layer and changes specific to clone in another RW layer (basically what Docker does). I know Ansible has somehow solved the problem of running same config scripts multiple times, but is it 100% bulletproof?