GoogleShirker what does the sandboxing do?
If an app is infected with a virus, it's very difficult for the virus to spread to other apps or the system. The virus has the same permissions as the infected app.
Apps can still talk to each other. They have to be explicitly programmed to each other. Or there could be generic functions.
Probably most people just need owner or owner + private space (PS).
You can install apps from owner to somewhere else.
PS: settings > security > private space > list available apps pick some
Another profile
settijgs > system > user > [pick a user] > list available apps
The play store can be anywhere you want.
Scenario 1: on the owner profile. Then transfer apps elsewhere
Scenario 2: lots of play stores (Some apps dynamically download extra tools or information from the play store automatically. 1 example of this is if an app needs to scan QR codes, it'll need the play store in the same profile/PS that it resides in to download QR code scanning info. You might be able to get this downloaded then transfer the app using an app like amaze to back and restore the app elsewhere.)