alt Hacker NewsFeels like you don't know what "the sandbox" is. It's not "their" sandbox, it's from AOSP.
When you run an app on Android, it runs in a sandbox. Meaning that your social media app cannot access the files of your banking app by default. They are "sandboxed".
On a normal Android, the Play Services are installed as a system app. It is privileged app that has "system" access. A system app is not sandboxed.
GrapheneOS allows you to install the Play Services and the Play Store as "sandboxed" apps in that they run unprivileged, just like WhatsApp or TikTok or your banking app.
So running the proprietary Google apps in the sandbox is obviously more private than running them as system apps, wouldn't you say?
If the Tiktok app passes your data to Play Services (say, to support notifications with GCM) then it doesn't make any difference that Play Services is nominally "sandboxed".
I agree there's some marginal benefit that sandboxed GApps need to prompt the user for permissions (rather than having privileged system level access) but at the end of the day, Google Maps will get GPS perms and Google will know everywhere your phone goes.