My $0.02 here is that people who believe that pointing and clicking is the fastest way to get something done when available
are wrong, especially if what they are doing is typing to start with. I never use the button for tags like "code", I just type "code" in square brackets, etc.* You can do that at least 4-5 times in the time it takes you to grab the mouse, labouriously highlight a paragraph, and click on an icon.
If you think I am even potentially wrong about this (or that it is "subjective"), consider what it would be like if instead of using a keyboard, you put sentences together by selecting words from a drop down menu.
Just type "code" in square brackets, dude. More shiny widgets tempting you to make simple things more complex are not going to help anybody.
* except after the fact, ie, when I'm reading over instead of typing. Then I go
crazy with the mouse highlights
. But I suspect the "quick reply" is not intended to involve a lot of post composition emphasis.