The logic of the audiophile in this specific case is that the DAC chip in the original playstation (The chip that takes an audio cd's 1's and 0's and converts it to analog waveforms) was a "high quality" DAC normally found in more expensive (at the time) CD players and that the playstation was therefore a secret high end CD player.
Audiophiles have a real love hate relationship with digital music. In the analog audio days, where the entire chain from recording studio to bedroom stereo was all analog, a lot of the woo shit did matter in bringing out clarity and sound stage in a given recording. With digital, it matters far less, but the audiophile mind still needs something to tweak, so they're obsessed with "jitter"; micro vibrations causing misreads on digital music that cause "distortion" in playback.
Of course, as you see with these mods, the fact that the PS had a good dac only sustained them for so long before they started looking for other things to tweak. Aside from visual changes (Your high end CD player cannot look like a game console for children, especially if it's on top of your $10,000 Amplifier), they start doing things like separating the power supply from the case (and likely replacing it with something that causes less "distortions" for an extra $1500 please). Occasionally you'll come across Mac Mini's that have had the same thing done to them for equally dumb audiophile reasons.
So no, in the end the player doesn't really matter and your average consumer would get far better return just buying slightly larger speakers. But the audiophile already has those, and the hobby is about the chase to find the perfect component to fill in gaps you imagine you have.