How is the Sky Pup different from any other two-axis craft in that respect? Ercoupes have been landing crabbed for 80 years.
Rudder two axis are a little different to ercoupe style aileron-rudder linked airplanes. As you point out in both types of airplanes, if they are tricycle geared, you fly final pointed to the wind and land crabbed and the stout tricycle gear automatically aligns with the ground roll due to its CG position. No need to slip.
However on a Ercoupe you have direct control of the two axis that are critical close to ground- ground track and roll axis. If the wing drops close to ground in the Ercoupe you can directly (rapidly) pick it up with ailerons or if you need to align with runway you can turn with ailerons and linked rudder. You have direct control in both cases. The Ercoupe after all uses control surfaces on all three axis even though the pilot control two of them together and so cannot cross control to slip/skid.
On a rudder airplane you pick the dropped wing and turn to align with runway indirectly as the only direct control is yaw. This can make a difference when you are close to ground in gusty conditions and need rapid control response.
All in all many 2 axis rudder planes have been and continue to be flown safely but all things being equal they provide a little less (rapid) control in landing than an Ercoupe. I am a big fan of rudder two axis planes for fun UL flyers.