If you install apps from F-Droid (an alt app store on Android), they are all open source and built by F-Droid themselves. The benefit of this is, zero malware. And much better privacy. It's a nice peace of mind. The Play Store and App Store don't have such a good track record. And there's a lot of great apps on F-Droid (like clients for Twitter, Reddit, Hacker News, etc)