This setting won't in itself stop you using any apps. But apps can (I think) determine where they were installed from, so a banking app might be able to detect

This setting won't in itself stop you using any apps. But apps can (I think) determine where they were installed from, so a banking app might be able to detect this and bail out. Google's Android (don't think this is in AOSP; probably tied to Google Play Services) also checks non-play-store apps for malware on your phone, and might reject them if they contain malware. Some apps also try to detect rooted/jailbroken phones and won't run (or at least give a warning) in that situation.