The problem with making it an option alongside those ones would be: How is it supposed to behave when there are none present anywhere near the route you're requesting? That's why it is a toggle on top of your normal route type preference.
Okay, I see a slight bit of a point there, but I don't see why you seem so adamant that there is no issue with this. I was one route away from deleting Waze because I didn't realize how adversely this option was changing my routes. Luckily I figured out my stupid mistake and become a true fan. Had I given up, I would not have discovered cartouche and my area would not have benefited from the few thousand map edits I've done already in addition to all my driving statistics.
Perhaps it should automatically shut road munching off after each session and not be left as the selected default. Really, who is going to use Waze for cookie munching most of the time? People with plenty of spare time and money for gas I guess, but most users would only want to do this on occasion. Or maybe a warning when you select a route that road munching is enabled to remind you that route is not optimal. Waze has enough issues with map connectivity, directional problems and bogus standstill traffic data. Why add to the problems by having a feature that deliberately gives inefficient routing information without proper explanation.