Imo it is not possible for google to detect properly spun content, it is not worth computing power it requires. They can do this using ngrams for example, but it is uses a lot of queries. And for example article spinner I coded beats this algo, so google cant detect that the content is spun. Manual spinning is also good but it takes more than 30 minutes per article.
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.
In this harsh industry who can't implement a small number of extra profit? Another upside will be that you can construct right up your cache of primary subject material and help to increase your good reputation for posting and potentially attract some more significant paying users. Lastly, simply just believe that of the experience you can be developing by owning to groundwork some of the ideas you generate about. You can be, or will be soon, a fountain of inadequate information.