On Sunday, February 26, 2017 at 6:37:23 AM UTC+3, wrote:
Side slip for all the above reasons, especially for instruction. Translating from crab to slip in the flair or just at touchdown is unnecessarily complex. Establish the forward slip on final and hold that attitude until stopped.

I don't know anyone who "transitions from crab to slip in the flair [sic]". You simply straighten up with wings level, and accept whatever minor sideways component the crosswind gives you in the two seconds before you touch down. Either you touch down going very slightly sideways, or you yaw a little past the runway heading to align with the direction the glider is actually going. Or, I guess, you could fly your final with a track slightly upwind of runway heading so that your track gets aligned by the crosswind during the flare.

It doesn't really matter on the wide lush grass runways we fly gliders from.. Maybe it's different if you're landing on a strip of concrete only a couple of meters wide.

Maintaining a slip all the way to the ground isn't a good idea in the long span low wing gliders we train in, especially if the grass is lush and/or uneven. Wings level!!! Again, it may be different in a 2-33.