For businesses who are promoting themselves locally, Google Plus is essential. That's because Google+ Local (Google Places) businesses are displayed prominently in search results for searches containing local search terms.
It's great to have a business that is active locally because many people search for local businesses and, as a result, are more likely to buy if they find you just round the corner in their town.
In fact, any business (with local customers or not) should probably get a Google Places listing. There's no reason not to. Google Places for Business is still the way to get listed but this has been merged with Google+ Local.
So, the lesson here is to check your Google Places listing or create it if you don't have one. Visit Google Places for Business to do this. After you have created and verified the listing it will appear as a 'Place page' in Google+ Local. However, in fact, it's probably a good idea to create a Google+ page1 for your business as well. This means that you can post articles and links to a relevant audience (assuming you connect with people and grow your Google+ Circles).
In addition to the local business aspects, it's becoming more and more evident that Google+ is increasingly important for good search engine rankings. Like it or not, Google+ is here to stay and we think you need to be active there.
1 There is a difference between a Place page (Google+ Local listing, derived from Google Places for Business) and a Google+ page as described here. The Place page contains business information and can have scores and reviews whereas the Google+ page is a social network page that has similar features to your personal/individual Google+ account. We think you need both.