Please justify use of required Observation resource in QuestionnireResponse.item.answer.value. It appears that using an answer value with LOINC code, instead of Observation, would align with SDC IG and use of extract operation to create Observation resources from the QR answers, without requiring the answer to be an Observation. As written, this IG will prevent use of the growing ecosystem of open source and COTS tooling for rendering SDC Questionnaires and extracting Observations, from the Response.