I take it the saw board is so you don't scratch surface of the material you are cutting.
No, not at all. I thought I said it somewhere up there, but even I can't be troubled to read what I write
The sawboard is to remove any guesswork from the equation when cutting your material.
Normally you'll have to measure the offset of the side of the shoe on your saw. To use your fence, you'll have to measure your line, and then using the offset measurement of your saw, place your fence that far away from the line, and THEN make your cut (and I have yet to see a saw that has the blade perfectly on the exact edge of the shoe).
With a sawboard, you simply place the edge of the sawboard on your cut line, and run the saw down the sawboard. No guesswork, no nothing. Just clamp it on there and your offset is automagically accounted for. The shoe rides right along the factory edge each time, therefore the edge will always be the cut line
Hopefully these pics will explain what my words might not be doing so much goodly worky worky at on the day after yesterday