reducedBW-FR1 in UEAssistanceInformation Message

3GPP TS 38.331 v16 states that Value mhz0 is not used for reducedBW-FR1 in UEAssistanceInformation Message when indicated to address overheating. Why?

As per ReducedAggregatedBandwidth ::= ENUMERATED {mhz0, mhz10, mhz20, mhz30, mhz40, mhz50, mhz60, mhz80, mhz100, mhz200, mhz300, mhz400}, mhz0 is valid value