Well.. the screen you are looking at is the vendor’s Pro Dashboard. They can choose those rates, which will be their standard shipping default rates.
They can still override on a per product basis.
Admin can still set rates within the admin > woocommerce > settings < shipping > vendor shipping
Vendor Shipping rate priority is still handled as usual:
If per product rate / override exists: this shipping rate is used.
If no per product override exists, store default rate is used.
If no per product rate and no store default rate exists, admin default rate is used.