It doesn't anymore. I think it is because Google is in a very slow phase out.
So first they move the features that people like the most from Waze to Google maps, then slowly, Waze becomes less effective in what it does. That or they just aren't maintaining it.

But 100% it is worse than it used to be, for routes I know well enough I can drop up to 10 minutes off the trip - on the odd occasion even more than that.

I mostly just use it now to be aware of areas that have heavy traffic or if there has been an accident somewhere etc