Question about sub-site settings

Hi there,
I noticed that in several places in the settings of a subsite (via this example URL:, the site URL is the subdomain URL where the subsite is located, for instance

I mean these locations in the site-settings:
- site-address (URL) in the General site-info tab
- in the settings tab:
- site URL
- home
- fileupoad URL
- some plugin specific values
- Ossdl Off Cdn Url (don't know what that's for, it comes back in all sites...)

Isn't it better/doesn't it make the sites faster when I adjust this in the mapped domain URL like ?

I tested and it does no harm, it seems, except an occasional image that get's 'broken'.

What is your advice here?
Adjust or not to adjust?

Thx for your help!!

Best regards,