Dotnet bulk subdocument API

Thanks for the link to those docs, for some reason that didn’t come up in any of my searches. It’s not 100% clear to me how to take advantage of batching though. This statement:
“When using an SDK in an asynchronous (non-blocking) model, all requests are inherently batched.” suggests that all i need to do is make sure I’m using CompleteAsync() on the subdoc API and batching will be handled internally?

but then why do we need to manually batch as demonstrated here?:
https://docs.couchbase.com/dotnet-sdk/2.7/batching-operations.html#batching-operations-using-sdk