Such explanation is also included in Dynamit Nobel Defence marketing brochure:
For the same reason they developed CLARA ERA with composite plates instead of metal ones.
However, almost all weapons with SC that have been designed for last 30 years still have warheads with precursor. Modern ERA have improved reaction time, good example of this is russian 4S24 in comparison with 4S20.
Moreover, thick passive plates placed in front of reactive armor can significantly erode jet tip and reduce its velocity. For example there is 50 mm of steel between ChSKW-34 layers in Duplet from Oplot-M hull and 25 mm in front of 4S22 in T-72B ob.1989. Even 10 mm thick steel plate has noticeable effect.