The new "New Document" dialog introduced in CC 2017.1 is useful and saves times in creating documents from scratch.
To name a few, the dialog provides the following advantages:
1. Instead of beginning with a blank document, you can choose from a wide variety of templates, including templates from Adobe Stock. Templates include assets that you can build on to complete your project. When you open a template in InDesign, you can work with it just as you would work with any other InDesign document
2. In addition to templates, you can also create a document by selecting one of the numerous presets available in InDesign
3. It allows to name your preset right at the very begining instead of starting with an untitles document
4. Also, specify the unit system (Pixel, picas etc) you may want at the very begining
5. Moreover it is consistent with the "new document" dialog in Photoshop and AI
Never looked at it in this way
And you can turn off the new "New" dialog box by checking "Use Legacy 'New Document' Dialog". I prefer the legacy dialog.