Why isn't the OnePlus 7 Pro compatible with Google Daydream?

Is there any shortcoming in the hardware offering of the One Plus 7 Pro that makes it ineligible to run Daydream ? I can't see anything that specifies what *exactly* makes a Daydream phone special . I see the [YouTube VR page in the Play Store](https://play.google.com/store/apps/details?id=com.google.android.apps.youtube.vr&hl=en_US&rdid=com.google.android.apps.youtube.vr) says that my hardware isn't compatible. But it doesn't tell me why it isn't compatible,