What is the purpose of the "aws vpc endpoint route table association" resource


I created a gateway vpc endpoint for dynamodb using the aws_vpc_endpoint resource and routes got automatically created for the prefix list in the specified route tables.

I am wondering what is the purpose of the aws_vpc_endpoint_route_table_association resource.

As I think it is also doing the same thing of adding routes to route table for that service, which AWS is automatically doing .
Am I missing something.