It's important to note that this new ad slot "will allow advertisers to promote their apps across the whole network, rather than in response to specific searches." This is exactly Facebook's game, and the underlying technology they use to target these ads could easily be repurposed for oh, I don't know...a new search engine?
Coincidentally, iOS 13 updated iBeacon in a way that also made it a lot less useful to developers (although there was a clear privacy benefit for users.)