The “first-of-its-kind” superlative likely refers to the combination of streaming and downloads, as this isn’t the first high-def streaming service to hit the Japanese market. Amazon Music offers its HD service in the country, and Sony Music Entertainment Japan ran a high-def music streaming service called mora qualitas, until the service shut down in 2022.

Also Deezer does not offer HD streaming, i.e. better than CD quality at 16bit resolution and 44.1khz sample rate.

“CD quality” is that the audio is at a resolution of 44.1kHz/16-bit. HD/only matters if you have the equipment and I think my idea here was good