While Google is still testing and fine-tuning its Local search page’s info structure and User Interface (UI), it is obvious that Google values “Mobile-friendly” as one of the major website attributes because it will offer a much better User Experience (UX) on mobile devices.
On a 11/18/2014 post by Google: A mobile-optimized site will get a “mobile-friendly” label on mobile search results, “We see these labels as a first step in helping mobile users to have a better mobile web experience. We are also experimenting with using the mobile-friendly criteria as a ranking signal” (source: Helping users find mobile-friendly pages)
To test if your website is “Mobile-friendly” by Google’s standard
Simply type your site’s URL in Google’s Mobile-Friendly Testing Tool, it will give you indication if the URL meets the requirement, it may even provide extra findings for you to address.
For example, below is a screenshot of our website homepage testing result:
