The reason Kubrick used them was not for their depth of field, but because he was shooting on far slower film than the digital sensors available today. They're relatively pointless today except for their historical/curiosity value.
But yes, the film speed was an issue, since you can't exactly use mega-fast film for 35mm or the grain will be distracting.
Proper use of lightning is part of the art. The hardest part for the movie photography director.
What you are saying is that it was better for this movie, as a picture would be better for a realist painter's work.
There are millions of finely executed motion pictures with great image that gave your eyes the impression you were seeing actual candle light, without feeling it was underwater, like Kubrick did.
There is nothing at all natural about using several hundred candles in a room. No one would ever do that - a room that size would get 20 at most.
If he had actually used 20 candles and added extra light carefully tinted to match the color of a candle it would actually end up looking much more natural. But then no one would talk about it.....
Today, you could shoot the same scene at ASA 800 with an f/1.4 lens, which is readily available.
Thinking that other nerds must be talking about it[2], I found a great thread discussing the ~20cm DOF @ 3m and the tradeoffs that would be involved in shooting a similar setup today. http://reduser.net/forum/showthread.php?65115-Barry-Lyndon-C...
[1] http://www.imdb.com/title/tt0072684/fullcredits
[2] I've been fixated on the New Wave and crusty mise-en-scène and so discussion of Kubrick only comes up about once a year. It's always Barry Lyndon, this lens, and how much better the film would have been without Ryan O'Neal. :-)
My guess is the hype engine will focus on the idea that if 48 FPS is "twice as good" as 24 FPS then 96 FPS is even better.
In true Hollywood style I bet they'll be post processing to make scenes look like they were filmed with standard lens.
On the topic of FPS, though, that's definitely an ongoing issue. I wrote up some of the most salient points a while back here, if you're interested:
It would be unusual to shoot on film stock as fast as ISO 800. In most cases 500 would be the highest. The scenes in Barry Lyndon shot on the f0.7 lenses were actually filmed on ISO 200 stock, partly to avoid too much grain.
Standard film stocks would be 50, 200, 250, and 500 ISO. I know that nowadays Kodak don't produce 35mm film stock greater than ISO 500 (unless as part of a special order).
Of course, Stanley Kubrick shot Barry Lyndon before the widespread availability of T-grained film. Thus, the high-speed film available in 1975 would've been much grainier.
You intentionally underexpose the film when you shoot, pretending that it has a higher ASA rating than it actually does.
You then increase the time and/or the temperature when developing the film, to compensate for the underexposure. You end up with a correctly-exposed image, but at the cost of extra grain, extra contrast, etc.