Apple is switching the default provider of its web searches from Siri, Search inside iOS (formerly called Spotlight) and Spotlight on the Mac. So, for instance, if Siri falls back to a web search on iOS when you ask it a question, you're now going to get Google results instead of Bing. Updated below with a statement from Microsoft.
Consistency is Apple's main motivation given for switching the results from Microsoft's Bing to Google in these cases. Safari on Mac and iOS already currently use Google search as the default provider, thanks to a deal worth billions to Apple (and Google) over the last decade. This change will now mirror those results when Siri, the iOS Search bar or Spotlight is used.
(Score: 1) by Paradise Pete on Wednesday September 27 2017, @11:19AM
Microsoft must have been paying a fair bit of money for that each spot, but there's probably not much revenue in it as no ads appear and no stop is made at a bing page. Much different from a normal search. So I'm guessing that Microsoft didn't want to keep paying.