Google announced in a blog post that they rank https sites higher in search results. The search monopoly says that they are already do this since the past few months. They include https into the set of signals they use to rank sites. So far only 1% of global queries have been affected, but Google may decide to strengthen the signal.
Google wants to encourage all website owners to switch from HTTP to HTTPS. So what if you just run a blog where you do not have to login or share any personal data? Why would these sites need HTTPS? Just because Google says so.
A SSL certificate means additional cost per year and technical effort. You pay about $200 per year for a 2048-bit key certificate. Forget about getting a cheap SSL certificate. Google states in the post that you should use 2048-bit certificates. I assume you should go right away for an EV SSL certificate for good measure which costs even more. Again Google is favoring corporations over individuals and enthusiasts.