docs: Update structured metadata docs (grafana#12187)

docs/sources/get-started/labels/structured-metadata.md

@@ -15,8 +15,16 @@ Structured metadata is a way to attach metadata to logs without indexing them or
 kubernetes pod names, process ID's, or any other label that is often used in queries but has high cardinality and is expensive
 to extract at query time.
 
-Structured metadata can also be used to query commonly needed metadata from log lines without needing to apply a parser at query time. Large json blobs or a poorly written query using complex regex patterns, for example, come with a high performance cost. Examples of useful metadata include trace IDs or user IDs.
+Structured metadata can also be used to query commonly needed metadata from log lines without needing to apply a parser at query time. Large json blobs or a poorly written query using complex regex patterns, for example, come with a high performance cost. Examples of useful metadata include container_IDs or user IDs.
 
+## When to use structured metadata
+
+You should only use structured metadata in the following situations:
+
+    • If you are ingesting data in OpenTelemetry format, using the Grafana Agent or an OpenTelemetry Collector. Structured metadata was designed to support native ingestion of OpenTelemetry data.
+    • If you have high cardinality metadata that should not be used as a label and does not exist in the log line.  Some examples might include `process_id` or `thread_id` or Kubernetes pod names.
+
+It is an antipattern to extract information that already exists in your log lines and put it into structured metadata.
 
 ## Attaching structured metadata to log lines