What are the differences in casual controls and regular controls?

Solution 1:

Casual Controls allow you to play with single JoyCon, be it right or left.

  1. Right stick can move both character and menu
  2. Arrow buttons are turned into action buttons. UP is X, DOWN is B, LEFT is Y, RIGHT is A
  3. Right stick click will work as whistling

In both modes R/L and ZL/ZR works as accept button in most menus. Only downside of enabling Casual Controls I have noticed is loss of "D pad" for browsing menu.

Casual Mode affect Pro Controller as well as JoyCon halves, it is safe to assume all controller types are affected.