Request about core:archive with cron task

Hi to all
I’m a newbie with Matomo, so please excuse me if i’m asking you silly questions.
I have installed Matomo on the matomo . domain1 . com and i’m adding sites for tracking, such as… domain2 . com, domain3 . com etc…
I have read how to setup a cron job on matomo website but it’s not clear to me the following argument:
Why do I need the “url” parameter and which domain should I put here? The domain where matomo is installed or the domain of one of the websites for which I want to track traffic?

In the documentation:

Then in your case, you should provide --url=

Ok, but why the suggested solution for Plesk is different?

/opt/plesk/php/8.1/bin/php/var/www/vhosts/ core:archive --no-ansi 
>> /var/www/vhosts/

Here the --url parameter is not used… why?