AWS Lambda Function CloudWatch Logging and Permissions Documentation Restricting

It seems like under the aws_lambda_function documentation for CloudWatch Logging and Permissions that the policy could be more restricting.

Couldn’t you utilize the aws_cloudwatch_log_group ARN output to only allow it to log to that specific ARN?

Also, slightly confused about the purpose of the logs:CreateLogGroup action. We already created the log group in the example, so why do we need to give permissions to create log group?