Well, HTTPS has its benefits and more than 58% of top 1 million websites as per Alexa are now on HTTPS. Now thats something. So what do they get out of it anyway?
HTTPS is Trust
Google Chrome, Firefox and Internet Explorer mark websites that are http as "Insecure" in the address bar. This can negatively impact the trust that users have on your website. On the other hand, seeing the trust seal of a green security lock icon, will boost your user's trust in your website. This is especially crucial if you are selling or other monetary transactions on your website.
Boosted Google Ranking
Consider the ranking of two entries in search results whose all other signals are equal. It is guaranteed that in such cases, HTTPS is the deciding factor in which comes first in the search results. Personally, my dictionary-like website www.niftyword.com was launched https-first when most sites had not yet invested in https and that immensely helped climb the ranking ladder to reach the top spot.
Google goes Mobile first
Google is slowly moving towards crawling only the mobile version of the websites. For mobile websites, https figures as a major component in ranking. So https will only grow in importance for search ranking.
AMP needs HTTPS
AMP is Google's answer to overstuffed, bloated websites. As such, Google prioritizes search results with AMP, especially for devices with smaller screens aka mobiles. Of course, mobiles have overtaken computers in usage a long time now. So there is a mad scramble to make blogs AMP compliant. HTTPS is a prerequisite to implement AMP
Don't lose Referrer data
Referrer data is very crucial to determine where your traffic is coming from and how to grow them. Unfortunately, browsers no longer send referrer data from https websites to http websites. Say, your website is http. The user clicks on a link on website https://example.com to come to your site. You will get no referrer data regarding https://example.com . Adding https facility to your website keeps your incoming referrer data intact.
First line of defence against Hacking
HTTPS prevents others from snooping the data sent between you and your user. It prevents malicious agents from usurping your website. Without HTTPS they could easily hijack your website, even if it is a plain html webpage. They could add their own content , add ads or even malware. When that happens, you will also have to handle malware warnings from Google.
Make your site faster
The performance penality for of having HTTPS enabled is negligible. With HTTP/2 enabled, ( HTTP/2 needs HTTPS), there is significant speed up in pageloading and fewer connections to your server. Winnings for everyone.
All these benefits can be yours with a small amount of initial effort and no cost. We recommend Let's Encrypt as they provide free certificates with 90 days validity and auto-renewal. Let's Encrypt is a free, automated, and open certificate authority brought to you by the non-profit Internet Security Research Group