There are three benefits to implementing Always SSL (HTTPS): “Security,” “SEO,” and “reducing user distrust.”

Reasons to implement SSL

Excluding security aspects, there are mainly two reasons to implement SSL.

SEO benefits

In 2014, Google officially announced that they would “use HTTPS as a ranking signal,” meaning it would be used as criteria for search rankings.

• Google ウェブマスター向け公式ブログ: HTTPS をランキング シグナルに使用します

Some browsers like Chrome display "Not Secure" warnings

Soon Google Chrome will mark all sites that don't use HTTPS encryption. Starting with Chrome 68 released in July, Chrome will prominently display all HTTP sites as 'not secure' in the URL bar.

• Google Chrome、非暗号化（HTTP）ページに"not secure" の警告を表示 | TechCrunch Japan

I think we can’t say for certain that site visitors won’t feel anxious when seeing Chrome browser’s “Not Secure” display.

That’s all from the Gemba where I recommend implementing SSL support for all pages without leaving any HTTP pages, based on these two reasons.