I upgraded a full Y ticket from ARN-IAD but UA and SK have zero integration so my ARN-CDG leg did not upgrade. I explained at the gate -- she said that she would be happy to upgrade but they didn't have the catering.
It doesn't make much difference on SK intraeurope -- you get the same seats with the moving curtain concept. Once I was on a flight to BRU and the business section was about 3/4 of the plane.
SK only awards flown miles. I found that out when I got ~17 miles (!) for CPH - Malmo on the boat back in 2000. Is this a record low mileage award for a "flown" segment? And I was looking to forward to 500 miles for the boat ride!
Just to explain... you depart from a terminal gate and walk down to a bus that takes you to the water at the edge of the airport property. The bridge of course eliminated this service.