Basically Chromium is just the good stuff, with all of Googles proprietary spyware stripped off and it has been packaged by Debian devs, and Debian frowns on spyware. I think that it is relatively safe to use, but I would be careful what extensions you install and of course change the default search engine to DuckDuckGo or something similar and if you use any of the Google services like gmail or YouTube, change your preferences at https://myactivity.google.com to avoid the data collection.