The industry is [federally mandated to move to FHIR](https://www.cms.gov/Regulations-and-Guidance/Guidance/Interoperability/index) and FHIR is easier to work with. Also, synthea supports FHIR.
The industry is federally mandated to move to FHIR and FHIR is easier to work with. Also, synthea supports FHIR.