These ads are important, because they can advance production tasks or help you achieve objectives.
There are 2 reasons why you might not be able to see Simcity BuildIt ads in the game:
1.- Because of configuration problems in the game.
Go to Settings (top right tool icon in the Simcity BuildIt game itself) --> About --> Info Exchange, and check that "Usage information exchange" is enabled.
2.- Due to configuration problems in your cell phone.
To solve it, on your phone or mobile device, go to Settings --> Privacy --> Ads, and then check that the option "Disable ad customization" is disabled.
(*) Contributed by QuimCity and Avi