Yea mate, WordAI really is overpriced IMO too, which is why I didn’t rank it higher in the cost-effectiveness rankings. Now, it did change more than a few words, but I see how you would think it’s less than 80% unique. TBS is also great, but only in terms of functionality and the easy interface which allows manual spinning to be done quite fast. As for their thesaurus, I think they have a lot to improve.
It is also very helpful for people who struggle with the English language in general and writing in particular. A free article spinner or paraphrase tool makes it easier for them to get new content with minimal effort. The quality of content created with article rewriter is close to human written content if not equally good. To ensure the quality, you can edit content to fix any errors.