Is this method safe?

Yes, it seems like this method is safe. Otherwise, it could be used to easily affect your competitors.

We are confident that SERPS will continue this trend and gradually switch from focusing on backlinks and gear itself towards user experiences and user signals. We can already see this unfolding on YouTube. Videos on this platform were once ranked based on views, likes and comments. This type of content is now being ranked based on how quickly a viewer leaves the video or if they watch all of the video. The same factors and trends are now becoming visible in Search Engine Result Pages (SERPs).

You need to leverage any and all the methods available out there, or else your competitors will!