The last thing you do in Super Mario Brothers is get thanked by the Princess.
The last thing you do in Super Mario Brothers 3 is get TRICKED by the Princess!!
I never thought about this before but in both endings Peach speaks to Mario, then takes the tone of the developers speaking to the player. By 64 this character/narrator role would be shared by Mario, but in these games, Peach is the only one with the voice and rotated body to address the camera. And convention now is to put developer narration inside bland text boxes to let you know you don’t need to care about them - not very theatrical or true to the medium, more like legalistic warning labels.