As someone who played the Japanese version of Catherine (read: the one with the messed up difficulty that was patched and is still harder than the US edition) at launch, I would wholeheartedly recommend still playing as a sort of experiential, "it's the journey and not the destination" sort of thing. I really, really enjoyed the puzzle mechanics and would be very happy to wage a defense of why that stuff is integral to the game's identity, but it's totally the bar stuff and all the socializing that I remember most about that game. There were definitely moments in those parts of the game where I was reflecting back on my own life and relationships, especially with the texts that you can respond to. It's not always perfect at what it sets out to accomplish, but what it does right in terms of atmospherics and whatnot, I feel it's done very well and it can only really be fully grasped by playing it yourself, I think. The story is only a small part of the equation; it's your own reactions to those beats and what you do in their wake that really make it a whole experience, in my mind.
Anyway, spoiler-wise, there's arguably an even bigger one to stumble into than the one you likely learned about, the implications of which I actually only grasped myself by reading the Japanese art book. And judging from when I've searched it online before, not necessarily a lot of English players caught onto it anyway even after beating it, so I'll stay quiet. Suffice it to say I think there's a lot still left of Catherine to experience even if you know that one part going in.