Isn't the Saemaeul-ho's service level or class not as high as high-speed trains?

Isn't the service level or class of the Saemaeul-ho not as high as high-speed trains or the Shinkansen?
Looking at it before, I thought the Saemaeul-ho provided service as good as the KTX or Shinkansen because the crew wore similar uniforms, but it seems that isn't the case.
When I was confused about where my seat was, they seemed to give much more casual directions compared to high-speed trains.
It turns out the class is exactly what you'd expect: better than the Mugunghwa-ho but lower than high-speed trains.
If comparing to overseas, it would be like comparing it to the "fake" Shinkansen in China.
Even if you consider them both high-speed trains, the class seems lower than the original Shinkansen in Japan..