This is exciting, but I really hope that Terraform will add support for it in reasonable time. These days I'd prefer to not manually manage cloud resources if I don't have to.
Google does (last I checked) put some paid time into systems like Terraform so that they support GCP well, but there's always going to be more of a lag, especially before GA.
I don't know Terraform well enough to know how big the lag is for new AWS features, but some lag probably exists even there despite AWS's dominant market share.
EOM
"This provider plugin is maintained by:
The Google Cloud Graphite Team at Google
The Terraform team at HashiCorp
"So Google can also help in this regard.
Do you know if they document their Terraform timeline policy for GCP anywhere?