Pretty sure that the point of an EMSEC zone is to enable the use of commercial off the shelf (COTS) computing gear for classified processing. TEMPEST equipment

Pretty sure that the point of an EMSEC zone is to enable the use of commercial off the shelf (COTS) computing gear for classified processing. TEMPEST equipment is very expensive and a SCIF obviates the need for it. None of the SCIFs I've been in had TEMPEST gear.