Google has globally rolled out App campaigns for engagement, and run across Google Search, Play, YouTube and mobile app Display Network.
“You can capture users’ attention and encourage them to come back to your app by highlighting new content or offers in your ad text, image and video assets. For example, you can highlight trailers for upcoming seasons if you want people to watch a new hit show, or delivery discounts if you want people to order holiday meals from local restaurants.
You can also showcase the most relevant content in your app by linking your Google Merchant Center or business data feeds to your App campaigns for engagement. Feeds give you a scalable way to keep your ads updated with your latest products and services. And they can do so in eye-catching formats and places where people will be spending more time during the holidays, such as the canvas below YouTube’s “in-stream” app promotion ads.”
App campaigns are able to link to business data feeds or product feeds in Google Merchant Center.
In order to be eligible for App campaigns for engagement, you need to have an audience size of at least 250,000 installs. Not only that, the campaigns have to be set up under separate account from App install campaigns. According to Google, this is to “ensure you’re optimizing for your defined campaign objectives.”
Source – Search Engine Land and Google Ads Help