CloudFormation is just for AWS Services. We use terraform for more than just AWS Services. HCL is also much nicer to work with than CF. I've also never found anything CF can do that TF can't. I have, however, found many things TF can do that CF can't.
I admittedly live in an AWS bubble when it comes to infrastructure and netops. I’m mostly a developer whose only expertise at modern netops and infrastructure is AWS. I could see where TF would be a better solution for infrastructure that spans providers.
As far as what CF can’t do with respect to AWS, most if not all of the missing pieces can be remedied with custom lambda backed resources and/or Python scripting with troposphere.
