Ah, didn't know that. I don't think it used to be that way, but I could be wrong there too.
Now, as long as it still handles traffic in that situation. The frequent routes feature used to just figure out what your frequent destinations were, when you would usually go to x, y, or z, and automatically set those destinations for you without any user interaction if you fired up Waze around the typical time for those destinations. So you'd get up for work and head out at around the same time you usually do, and it would route you to work without you hitting anything. Usually go to the park at 3pm on Sunday, well, it'd route you there automatically again when you fire up Waze around 3pm on Sunday.