The smartphone users will hit 270 Million by 2022 according to a survey. 67.3% of United States people are using since 2017, the number is increasing significantly and will reach 72.7% by 2021.
If you have a mobile version of your website, the user can navigate easily around your website. This will improve your user experience, improve time on page as Google gives priority to how many times a user spending on a page. You can improve your website speed as well as bounce rate. A responsive website will improve your local SEO score.
Every mobile search result showing local search results. The search is by default local search. When you are searching on your phone, Google automatically picks your location and shows you the local search results.
Ex. If you are in Sydney and you will type thai restaurant, Google will show you the list of thai restaurants in Sydney.