longer learning curve innit.
Skiing is easier to start but probably harder to master. Snowboarding depends on your natural balance and coordination a lot more at the start and yes, there is normally about one day of frustration, being a bit slow and falling on your ass.
That said if you don’t have a good teacher or aren’t as naturally well balanced and/or haven’t done a board sport before then it can take 3 days to a week (or until you give up)