How generated setter inside implements class from MapStruct

Question

greetings to all, in an example of a course we have used an entity and its corresponding entity that acts as a DTO that is called entidadRest but that annotates it with @json, what advantage does this approach have when performing DTOS, I am developing a mini project and I am using DTOS to use them with MapStruct but the fact is that when I generate the conversion, even though it generates and compiles them, it does not show me the settters

@Override
public Price dtoToModel(PriceDTO pricesDTO) {
    if ( pricesDTO == null ) {
        return null;
    }

    Price.PriceBuilder price = Price.builder();

        price.priceId( pricesDTO.getPrice_Id() );
        price.productId( pricesDTO.getProduct_Id() );
        price.brandId( pricesDTO.getBrand_Id() );
        price.starDate( pricesDTO.getStarDate() );
        price.endDate( pricesDTO.getEndDate() );
        price.priority( pricesDTO.getPriority() );
        price.price( pricesDTO.getPrice_dto() );
        if ( pricesDTO.getCurr() != null ) {
            price.curr( String.valueOf( pricesDTO.getCurr() ) );
    }
        price.price_List( priceDTOSetToPriceSet( pricesDTO.getPriceList_dto() ) );
        price.produc( pricesDTO.getProduc() );

    return price.build();
}

the form correct for that's price.SetPriceId( pricesDTO.getPrice_Id() );