Yup and this could easily be replaced on Microsoft's end.

Bing, Microsoft office, Android (these apps all work best on Android and Google legally probably can't block them lol), and Outlook.

Currently they don't see the adoption because it's easier to stay in the Google ecosystem for most people (myself included). If GPT sees right integration into them all however, this could significantly improve their value over what Google has if Google doesn't respond appropriately.

I focused on Mobile here but now that I think about it I'm not sure Microsoft even cares that much about mobile as most of their income comes from businesses.