"If Marni’s Secret Room is full on your current channel, then entry is not possible. Please try entering Marni’s Secret Room on another channel, or trying again later."

I have got this from blackdesertfoundry. What do you think "full" means? One player using it, two, five? This "secret room" might very well be completely useless. 

Typical PA. Good idea, tragic implementation.

I was expecting it to work this way, so you can say goodbye to your 1 hour a day in private zone.

It might be useful depends on what full means. According to blackdesertfoundry the private grinding is live on the KR server.