> Lufthansa 458 heavy, just for my planning purposes and for the Final controller's planning purposes, can you maintain visual separation with the aircraft at night?
> 458 heavy, exactly that is what is not allowed [laughs]
The controller was trying to give the pilot an out by allowing him to comply with his company's procedures prohibiting visual approaches, but allowing him to make an instrument landing so long as he was capable of looking out his window to ensure that he has specific other aircraft in sight. Note that this is required for parallel landings at SFO because of the very close proximity of the runways otherwise prohibits simultaneous approaches.
The problem is that, under the FAA regulations, all aircraft operating in visual conditions (which includes a clear night) have a duty to maintain vigilance "so as to see and avoid other aircraft" regardless of whether an operation is conducted under instrument flight rules or visual flight rules. 14 C.F.R. § 91.113 (https://www.law.cornell.edu/cfr/text/14/91.113)
In essence, the Lufthansa pilot was telegraphing his refusal to even comply with the basic flight regulations that all aircraft have to comply with (regardless of instrument or visual flight rules).
The combination of (1) refusing to accept a visual approach, and (2) refusing to even abide by the minimum requirements for operation in U.S. airspace (to see and avoid other aircraft), even on an instrument approach, caused the excessive delay.