There is an editor you can change your font, size, color. You don't get the editor in the "quick edit" you have to choose the full edit to get the editor. Just click "edit" not "quick edit". The quick edit is for when all you need to change is the title, price, category, etc.
When you click the edit button, the editor may not be showing. If not, you will see "Description: (Optional) Show »" and just click on "show" and then the word "hide" will be there and the description editor will open up for you.
They are working on making the site more user friendly. It isn't perfect, but it is getting better with every improvement that they make. The quick edit feature is one of the recent additions to make things easier when we don't need to change the description, but want to change other things.