4)- Less CPU noise? - Errrr ok too (Ain't that what LLC etc is for?)
They are talking about power ripple, cleaner power...noise is sort of another term for ripple though they are two separate things...why does that matter if you already have a PSU like Seasonic that is clean already? Beats me.
Not quite. The similarity is that both affect the waveform of the current, but that's it really. Remember that noise is a harsh, unwanted waveform in sound? The top is ripple, the bottom noise:



Sorry it's not very neat, I did it in mspaint quickly. As for why you want a board to deliver clean power, well what's the use of a clean input to the PWMs if the output is dirty? A clean input is good for your board, a clean output is good for your CPU.