Yup, but RedHat commit to backporting security fixes for the duration of the release (so 30/11/2020 for RHEL6)... Not sure that this is the case for software available via any of the collections.
"All Red Hat Software Collections components are fully supported under Red Hat Enterprise Linux subscription terms of service. Components are functionally complete and intended for production use. " [0]
edit: SCL's aren't supported by RedHat