I think you are confusing Local account with Standard User Account(SUA). A local account can be either SUA or Admin account and also a SUA can be Local account or a Microsoft account.
Passive Mode disables all active protection, such as shields and Firewall, so that you can use more than one antivirus program at a time without interfering with the performance of your PC or the reliability of antivirus detections. In Passive Mode, Avast receives all virus definition and program updates which allow you to manually run scans to check for issues on your PC, however Avast does not actively protect you.
- Avast FAQ | Avast Antivirus: Using Passive Mode