Hi there, @sylvainn… there is no shortage of content out there on privacy rules, and you should definitely check some of it out.
In general, though, the more restrictive you can make your rules, the better. So, if users are only allowed to view invoices that they created, then your second screenshot is the way to go because invoices a user didn’t create will never be “made available” to that user from the server regardless of what’s going on in the front end.