I propose adding valueSampleData and an optional choice  ( i.e., technically a slice that is not Must Support) to :

• US Core Heart Rate Profile 
• US Core Blood Pressure Profile
• US Core Pulse Oximetry Profile
• US Core Respiratory Rate Profile

By restricting the value datatype to Quantity, the current US Core Vital profiles, such as the US Core Heart Rate Profile, prevent conformant systems from using the sampledData data type for their use case even if they wanted to. There are several benefits to adding the FHIR sampledData type to select US Core vitals profiles:

1. Increased Flexibility: Allowing the use of sampledData type in US Core vitals profiles would provide implementers with more flexibility to accommodate the proliferation of home health monitoring devices that typically record periodic measurements, which are more conducive to using the sampledData data type.
2. Improved Data Transmission and Storage: Using a single Observation with sampledData can have benefits for both the data creator and consumer in terms of transmission and storage, as it eliminates the need for multiple Observations each with a single quantity.
3. Better Representation of Data: The sampledData type is better suited to represent periodic measurements, as it allows for the storage of multiple data points over a defined period of time.
4. Better User Experience: Allowing the use of sampledData in US Core vitals profiles would provide a better user experience, as patients can share their monitoring data with their providers more efficiently and effectively.

There could be various reasons why implementers would not use FHIR sampledData type:

1. Complexity: Using the sampledData type could add complexity to the implementation of US Core vitals profiles, as it requires additional information about the sampling frequency, resolution and data points, which may not be feasible or necessary for all use cases.
2. Incompatibility: The use of the sampledData type could result in incompatibility with existing systems and tools that are built on the previous version of the specification and only support the valueQuantity type.
3. Interoperability: There could be concerns about interoperability between systems using the sampledData type and those using the valueQuantity type, as the former may not be widely supported or well understood by all stakeholders.
4. Standardization: Adding the sampledData type to US Core vitals profiles could potentially deviate from existing standards and best practices, which could negatively impact the consistency and reliability of the specification.