Yes, you can now have Windows Spotlight as a desktop background. As explained in detail in this post, simply open Personalization settings > Personalize your background setting and select Windows ...

Jazz up your Windows desktop background with eye-catching photos One option is to find the images on your computer and then make one of them your background manually. All the Windows Spotlight ...

Now, expand the Personalization > Lock Screen settings. Change Background back to Windows Spotlight. Close all windows, sign out, sign back in again. The Spotlight ‘Like what you see’ box ...