Things are mostly not as good as they seem to be. Personally, I am a big fan of parallax websites. They’re beautiful to view, and kind of attractive if considered form a UX (user experience) perspective.
Mostly people think that parallax websites are not good for the SEO practices. They have a single URL, take time to load and are not mobile friendly. These are the things people say against these websites. But if we look closely, each of these problems arises not from their parallax design itself, but from the content distribution and SEO mistakes. Put differently, SEO problems come from wrong practices, not actually from the parallax code.
Let’s say, because storytelling using parallax seems so beautiful, then the website designers might be enticed to put several website pages worth of content onto just a single page. But putting hoards of content on to a single page is still considered as a bad SEO idea devoid of parallaxing it. For example, it’s wiser not to roll up your mission statement, case studies, philosophy, culture, project process, and contact information into only a single, long “About Us” page, instead, split some of those up to separate pages (especially the case studies).
But keep in mind, placing all this good content into just a single URL reduces your organic search engine visibility opportunities that could result in quite a few external links. If being found organically is your priority, then you’d usually do better for spreading out this content onto individual web pages. You can still use the parallax design on any of such web pages, just don’t let it be hindrance between you and your SEO-related priorities.
Make sure to hire an experienced SEO expert for your website, as it reflects what really your business is. Taking it for granted will hurt your online image and sales as well.