I totally get why someone would want to use a one button effect. Once you get used to the sound they create, it's a very, very quick way to get a sound you're after. To create a scratch track for a yourself, client, a producer or even a mastering engineer, you don't have to fiddle with dozens of knobs and buttons to get the sound you want. It's right there, one step, and very easy to dial in (Much like a preset on any other effect). There are going to be users that will say they never use presets and create every sound in their FX from scratch. That's ok too, but there is always going to times when you just want to dial in a quick and easy effect.
As to the look of the knobs themselves, I find the graphic on the knob, and the name of each, easy to read and understand. I don't think it detracts at all from the sense that Sonar is a quality DAW.
I too have wondered why Cakewalk would want to put in what essentially amounts to a second, propriety FX bin. I do however find myself using it in preference to the standard FX bin, as the graphics and ease of use make it so much simpler to use than just about any other DAW's implementation of an FX bin.