Moreover, I do not understand why superscript is possible for the "2" but not for the "3" as seen in the video. Makes no sense to me. Furthermore, I used arial in this example which is one of the most common fonts...
EDIT: I just tried it out for a few different fonts like Arial, Times New Roman, Helvetica. Only about 1-5% of all characters show the ability for sub- or superscripting. Unfortunately it is not obvious in advance what happens if one presses the buttons. Therefore, I think both buttons are generally useless in my opinion.