The Atari VCS, or Atari 2600 as it was better known as once it had been renamed a few years later, was introduced in 1977. This particular ad is from 1978 when it was still just known as the VCS (Video Computer System). It had been out a year or less at this point and as the picture shows, they were still selling the original heavy six switch model.
Throughout the years there were a ton of ads for the Atari 2600. There have been some really horrible ones and some good ones as well. This one is somewhere in the middle. Straightforward, a picture and a few facts without being terribly misleading or offensive which can be unusual for advertising. I believe that this early on it even came with all of the controllers pictured.
One other interesting thing about the ad is that it is advertising what must be one of the first screen savers. The ad mentions changing colors to avoid damaging your TV. Screen burn-in could be a problem, particularly on the CRT TVs of this time. To avoid this, when the system was on but the game had not been started or had ended, the colors cycled to a different combination every few seconds. This wasn't just an attract mode gimmick but a way to help prevent screen burn-in.
Read more: https://www.megalextoria.com/wordpress/index.php/2016/11/03/atari-vcs/