The DJ's at most broadcasting companies use records because it's easier to select specific tracks. So for promotional reasons record companies had to produce a small volume of high-cost records.
一般廣播公司的 DJ 為了選曲方便，一直使用傳統唱片，唱片公司為配合宣傳，也只得特製量少價高、寄送不便的傳統唱片提供 DJ 播放。