No, that's not what the rendering is for.
For the average user, rendering the timeline prior to export is a way of smoothing out the preview window so you get a more accurate view of what it will look like. If you don't, then your computer is rendering it on the fly which is why it's so choppy.
When you get into more complex videos with a lot of titles, mixing and so on, if you don't render it along the way, your preview window is next to worthless because the computer just can't keep up.
It doesn't affect the final export of the file and isn't needed most of the time.