If you want your content in front of more people and want to build your Google authority, joining Google+ and using Google Authorship is a must.
it will help. google likes to associate content with an expert and an identity. utilizing authorship will also help with ranking your content higher.
It helps to improve page authority and trust to your post . Also it helps to get traffic also. When someone see a smiley face and trusted face also then they feel more interest to read your blog easily.
Yes all are right ..google authorship is more important to success in SERP. Now a days Google consider social signal for higher ranking of website in serp.