Visitors can get a full SEO report on their website. They can also generate a pdf document in case the report is for their clients.
SEO analysis covers many aspects: content, links, keywords, accessibility, mobile, etc.
There are many languages available and the main language can be easily changed.
Only hosting is needed to operate the website (shared hosting is fine). There is no need for any other human intervention.
The income comes from AdSense or any other advertising network.