I think this kind of service is actually harmful to content providers. They can not benefit from the content they created if readers always consume it on the RSS readers. That's one of the reasons many blogger/website don't provide RSS feeds anymore.

The RSS aggregators should encourage readers to go to the original website. So when I got the chance to build my own RSS reader(https://feeds.pub) I only shows a title and link of an article to readers to drive them to the original website.