Allow instrument Enabled implementation to have additional optimizations and features

CHANGELOG.md

@@ -16,6 +16,9 @@ release.
 
 ### Metrics
 
+- Allow instrument `Enabled` implementation to have additional optimizations and features.
+  ([#4747](https://github.com/open-telemetry/opentelemetry-specification/pull/4747))
+
 ### Logs
 
 - Stabilize `LogRecordProcessor.Enabled`.

specification/metrics/sdk.md

@@ -999,14 +999,16 @@ must be retained.
 
 **Status**: [Development](../document-status.md)
 
-The instrument [Enabled](./api.md#enabled) operation MUST return `false` if any
-of the following conditions are true, and `true` otherwise:
+The instrument [`Enabled`](./api.md#enabled) MUST return `false` when either:
 
 * The [MeterConfig](#meterconfig) of the `Meter` used to create the instrument
   has parameter `disabled=true`.
 * All [resolved views](#measurement-processing) for the instrument are
   configured with the [Drop Aggregation](#drop-aggregation).
 
+Otherwise, it SHOULD return `true`.
+It MAY return `false` to support additional optimizations and features.
+
 Note: If a user makes no configuration changes, `Enabled` returns `true` since by
 default `MeterConfig.disabled=false` and instruments use the default
 aggregation when no matching views match the instrument.