The icon next to the word builds the association between the icon and the word. Users aren't all drooling morons with the memory of a goldfish. The first couple of times, yeah, you have to hunt for the right icon but after you know what you're looking for, the improved density of icons puts more tools within immediate reach. If tooltip shows the keyboard shortcut, even better!

The idea that everything should be immediately intuitive is ridiculous. Babies have to learn how to properly suck a nipple and how to chew food in order to eat. Why should we expect mastery of a much more complex tool to be immediate?