Yes, that's correct, as documented:
https://winscp.net/eng/docs/ui_pref_updates#automatic

The option is not available, if WinSCP was not installed using an official installer.

As for the why? - It is not implemented yet. You need another application to update an application. That's the role the installer serves here. An application cannot update itself, as it is locked while it is running. Of course there are solutions to the problem. But as, so far, there was no demand, it was never implemented.

Hello,

is it right that i cant enable the "Email address authorized to automatic updates" with the offical portable version? Why?

Regards,
Fabian