Medium Tail Keywords- Is it important in seo 2017?

Hi everybody,
Could you please help me to answer this question: Medium Tail Keywords- why is it important in seo 2017?
Thank you very much ;)

According to a study by Smart Insights, the highest-rated digital marketing technique of 2017 was content marketing. Long-tail keywords definitely help you rank better and help with both your SEO and CRO. However, they also ensure that your content provides real value to readers

For the sake of this article we are going to classify long tail keywords as being four-words-long or more, though there is some debate with people arguing that keywords that are three or more words long should be classified as long tail.Search marketers have generally accepted that the key phrase curve looks like the one below.It shows that a small percentage of traffic comes from 1-3 word phrases and the vast majority of traffic (around 70%) comes from the long tail (keywords that are four or more words in length).