@TylerGlaiel good points.
Interestingly, I have a different perspective when remembering me playing with both during my childhood:
With LEGOs I focus on the creation within the limits of the set. Exploring the game mechanics if you will.
Rarely I would incorporate anything not LEGO.
With action figures, it was mostly role play. Inventing stories with a personal touch surrounding the established lore.
Usually a lot of props which had nothing to do with the action figures were part of that.