Google added the option to add a slide from Google Slides into a document. Your chosen slide essentially appears as an image within your document. Once it is inserted into your document you can resize your slide and text wrap just as you would an image.
To insert a slide from Google Slides into your Google Documents select the "copy" option on the slide that you want to insert and then use the "paste" option in your document.
As with almost all new features, Google is rolling this one out over the course of a couple of weeks. If you don't see the new option today or it doesn't work as you expected, give it a day or two and then try again.
Applications for Education
I can see this new option being useful to students who have used Google Slides to create charts and diagrams for a presentation. Those charts and diagrams from the presentation could also be useful in writing a corresponding paper.