The implementation of an Infinite Scroll, when well established, will not influence the SEO performance of a website. The major advantage however, lies in optimizing conversions (depending, of course, on the objectives of the website in question!).
For example, one of the most documented cases is that of TIME Magazine, which managed to reduce its bounce rate by 15 percent simply through the implementation of an Infinite Scroll. The reason being is when users enter the Time.com website, they browse through several different pages of content without realizing they have changed pages multiple times. This increases the likelihood that they will view many content pages on the website during their visit. The main lesson learned in all of this is that a user is extremely lazy, and it’s up to you to make it as easy as possible for them to go through your content!
Thus, the implementation of an Infinite Scroll on your website may allow you to decrease your bounce rate and increase the amount of content being viewed, as well as the number of pageviews. This can be extremely interesting for sites whose main income comes from advertising with CPM ads (if the advertisement reloads when users change pages with Infinite Scroll).