All I know is that Google is one of the wealthiest corporations in the world, with probably the most specialist staff per cubic meter, who cannot possibly be fooled by SEO tricks any longer. They are getting more and more sophisticated by the day. I'm all for quality SEO strategies, the kind that the owner of Gigalicous persues. But I'd think that Google would look much broader than Google+1 for ranking a site. The +1 would probably get Google's attention, and then anything after that would have to pass some of their many quality tests as well.
Social signal is important for SEO. So its not only G+. Because we could driving many traffic from social network. Thats why google give more attention for website who had social network service feature.
Google +1 metrics are tracked by Google as are 200 or so other factors.
I always optimise my clients Google+ business page. This includes local business directory backlinks. I am confident that the work I do in this area helps dramatically with local business (maps) listings showing more often than not on page one for any web search where Google shows the map listings.
Perhaps more important in the future will be the ability to show these +1's as a social extension to Google AdWords advertising. The leaders in this numbers game will generate more traffic than competitors who lack behind, simply because social interaction and satisfaction builds trust.
Ignoring Google+ Business for too long will just put you behind in what is a rapidly growing social medium.