Places to eat at in Sapporo

I recently saw Vessel inn breakfast buffet at Sapporo's Nakajima. I tried to reserve breakfast tickets, but it becomes hotel reservations.

Can someone advice if I need to reserve or is it possible to just go straight to the hotel in the morning for their breakfast.

Thank you.

I had never seen such a booking option before! Interesting.

You need to select "デイユース" (day use) instead of "宿泊" (stay) in the search criteria (and yes, it's the same interface as the hotel reservation). Or there's a button on their description page, "Click here to purchase an outpatient breakfast ticket" (sic): https://www.vessel-hotel.jp/en/inn/sapporo/breakfast/