I'm curious about that as well. I was told by coworkers that Hashicorp added support for DynamoDB which rendered terragrunt redundant but I haven't had time to look into it.
Awesome! Any idea when this was added? I feel like this wasn't in the documentation a week or two ago; everything had still said "Use Hashicorp Atlas for remote state locking".
https://www.terraform.io/docs/backends/types/s3.html#dynamod...