I am also rather sceptical. However NLR is a respected organisation and it is likely that they are looking at the problems.
Yes, you will have to land banked, but the angle of the banked runway is designed to match the bank angle required at a specific radius of turn and airspeed.
Because I worked at Brooklands (running the Vickers/BAC research flight simulator), and in my spare time organised annual vintage car events for my car club I have some experience of driving around a steeply banked track.. The Brooklands bankings had an approximately parabolic cross section. The idea was that the faster the car, the higher up the banking you drove. There was a prominent black line painted on the track which was the optimum line for 100 mph. If you followed this at 100mph the experience was meant to be more or less hands-off.
So to land on a curved, banked runway you need to be flying a curve of the same radius of the track. This sets the aircraft bank angle.. If he lands at a point on the track cross-section where the track bank angle is the same as the aircraft angle everything should be perfect for a good landing. This is assuming that the circular runway has a similar cross section to Brooklands, After touch down, the pilot will need to gradually guide the aircraft down the banking as he reduces speed.
My experience of driving on the Brooklands banking is that it is easy when set up for a certain speed, but that slowing down and descending the banking is tricky. In my time there were only sections of the banking remaining and this made it more difficult.
I assume that NLR are developing autopilot guidance laws and landing aids for such an airfield.