First, you need to stop thinking about SEO as a "bag of tricks" to rank more highly in Google. "Will this get my website to rank more highly?" is the wrong question to ask in 2016.

The better questions to ask:

"What does my target audience want on a website, and how can I be the best one to give them that in the best way?"

"How can my website delight my target audience?"

Google is increasingly rewarding websites that provide a good user experience. If Google ranks websites highly that annoy people or return bad information, then that makes Google look bad in the minds of searchers.

In that context, hreflang tags are meant to provide a visitor with the optimal version of the site that it tailored to his or her country and language. So, in a way, it may help rankings in those locations if people have better, individualized user experiences. But you've got to start by looking at this issue in the right context.