If you are telling me that ILS is always available, never fails, and is at every airport then, then a visual should never be done.
If you are saying that even flying the G/S you never ever transition to a visual landing then again, a visual should never be done.
Unfortunately - none of these are true. Competency in flying a visual approach is required. On top of that, not sure it's particularly more effort (unless one has completely lost to skill to fly the thing by hand). Also, no evidence that the folks at the wheel were anywhere near dog-tired.
I'm saying that a crew should use every aid available if they are at the end of a longhaul flight. Yes, if it's LHR-JFK, with a quick flight time, and you've all had a good, restful couple of days off, then sure - go for the visual. But flying from London to LA in January, in continuous turbulence, when you were all up at 4am local............man, by the time (14 hours later) you are at ToD LA, you are shot, dead, knackered.
Under those conditions, you seriously think the crew would be wise to 'practice' a manual, no F/D approach? Are you Mad?
You say there is no evidence that those people were "anywhere near dog-tired".
I can only say - you must - must be a 100 hour PPL.