It would be great in cases where we just need a text element to have a switch to allow the most common text formatting such as bold, italic and underline.
I know we could just use the rich text element to get the formatting but some cases we just need to have the ability to make the text bold like in a large title where you just want to use bold to f.ex. highlight some features, make contrast, or in cases where we don´t want the user/editor to have the possibility to change (read: mess things up) as much as you can do with the rich text element.