Same here, has to be a bug (I reported to Waze). The menu bar should auto hide until you need it like Apple and Google Maps. If you map out a destination on Waze the top bar then auto hides - so my guess it is a bug rather than a "feature".
I haven't been able to get the black bar to go away in Waze without choosing a destination: if it's giving me directions, the black bar goes away automatically. If Waze is not actively providing directions to a specific location, the black bar stays on the screen. The same search/info bar in Google Maps, on the other hand, disappears automatically in every instance and reappears with a tap.
Waze has been working well for me so far. I'm glad to have the crowd sourced alerts and the speed limit on the screen. I hope that Waze shows when I'm exceeding the speed limit in a future update.