One of Atlas's creators here.
To be precise, we never analogized Atlas to Terraform :-) We said the existing HCL DDL is terraform like (which it is).
As far as I know, there are no heavily used terraform plugins for handling database migrations - and not because it's not possible.
The CLI currently exposes a declarative workflow (atlas schema apply), but we our analysis of the problem is that that declarative is not robust enough for many projects. For this reason, the Go API already support "versioned migrations" or "migration authoring" which means Atlas will generate migration files (SQL) and maintain the directory for you in the format that you like (Flyway, go-migrate etc).
In the very near future we will publish the migration authoring functionality to the CLI (you can already play with it via the Go package if you like).
There's also 2 deletion protection mechanisms for RDS (and maybe GCP DBs). AWS has built in deletion protection which is an attribute on the resource and Terraform has lifecycle protection which is a meta attribute you can put on any resource type.
The former disables the delete API (returns an error) on the AWS side and the latter prevents Terraform from running the destroy event (which includes replaces)
To be fair, they analogized themselves to Terraform, which can go as far as deleting the database itself (and all the other infra that goes with it). As with anything a good dry-mode and a good process around review is how you minimize the risk.