If the audience is management, the gain is control. "You just spent umpty million dollars redesigning your visual identity, you don't want some low-level copy jockey deciding to throw all that out and publish a page on your site entirely in Comic Sans, right?"
If the audience is the people who actually have to use the software, the gain is simplicity. "Look at this editing window from your current system. It has four toolbars, with fifteen buttons on each one! Do you really know what all those buttons do? Do you really want to be responsible to your boss if you hit the wrong one and screw something up? Now look at this other editing window. Isn't it clean? Doesn't it look easy to use?"