He's talking about stereo imaging for an audio signal. I'm going to assume you figured out that he was making an analogy between sample rates for digital audio and frame rates for video (recorded or computer generated). Since his ears are the engaged organs in this example, "hear" is the appropriate verb. And the creation of a 3D soundstage is the whole point of using stereo, as opposed to having a single channel for sound.
As for what it means to "hear" imaging, it's really obvious to anyone who's ever listened to a high-end system with a musical sample they're intimately familiar with. Better imaging means you can more precisely locate instruments in the stereo soundstage -- at the very least, better localization in the horizontal plane, and if you're lucky, the "height" of the soundstage may seem to expand. Instead of getting a smear of sound across some general area, you can point your finger and say, "I hear the oboe coming from right there."
Obviously, higher frequencies are more directional than lower frequencies, so some musical instruments localize better than others.
And no, you don't need gold-plated anything to get this kind of performance, but it doesn't hurt to have gold plating on terminals to prevent corrosion. I've had cables with RCA connectors on them give a poor, noisy connection until I've cleaned off the oxidation.
I will say, though, that after listening to a $500,000+ system at a local HiFi boutique and comparing to, say, my current approx. $5000 system at home -- a difference of 2 orders of magnitude -- I know that I'm missing out on some of what the top-shelf system can reveal to me, but not enough to justify the massive difference in price. (The high end system was fed by Mark Levinson equipment, with two massive monoblock amps plugged into 220V mains feeding the speakers. Pretty outrageous.)
On the other hand, I can say that SACD definitely provides a superior experience to CD, as the GP indicated -- the effective sample rate for SACD is ridiculously high, even though the technology isn't directly comparable since CD uses 16-bit PCM and SACD uses 1-bit DSD. DVD Audio, not quite as much, but I have heard some impressive DVD-A demos at 192 kHz sample rate, 24 bit/ch sample size, which were almost holographic.
The bottom line is, whether you're talking about audio or video, more samples/sec or frames/sec is a good thing, especially with (in the case of video) a rapidly moving subject. This truth is why, for instance, "Doc" Edgerton at MIT pioneered high speed cameras and strobe technology to photograph bullets ripping through playing cards. OK, in the still photography case, you care about the inverse of frame rate, so to speak, but the principle applies; I do know "Doc" also did film work, and even won an Oscar.