@wolfferine Just to be clear, it’s a common myth that iframes have a negative impact on SEO. Search engines view iframes as external links which simply means that the content being displayed in an iframe will not be indexed as content belonging to your website. The general rule is if the content to be displayed is important to your website’s SEO ranking (i.e. it contains a lot of keywords or keyword phrases) then you shouldn’t place it in an iframe.
In this case, we’re using the iframe to display a widget that provides a before and after image comparison. This is no different to using an iframe to display a youtube or vimeo video. Certainly, embedding video content through an iframe is not going to have any negative consequences when it comes to SEO. The bottom line is that iframe content will not enhance your SEO, but neither will you be penalised by search engines.