Interesting question! I'm sure this is largely subjective - but I prefer collecting CDs for the novelty of the physical object itself. LPs even more so; photos can't really convey the 'feel' of looking at or holding the physical copy in your hands.
As for the rips, there's not really any universal standard, and not necessarily any objective "definitive" version - as you both bring up, sometimes there are different versions found on digital platforms and on the original CDs; sometimes cues on the CDs are omitted from streaming/digital releases, sometimes the digital version contains additional material that couldn't fit on the CD due to size constraints, often they have different masters (some worse, some better), etc. etc. - but many times they are actually completely identical.
I'd argue the CD rips are still valuable as they offer the 'authentic', historical version of the release that shows how it existed at the time of release (giving certainty that it hasn't been "tampered" with), and sometimes the differences between CD and digital is only obvious when you have both versions available - but arguing over which is the better version of two lossless files that are actually identical but come from different sources seems completely pointless to me. It's like sorting a stack of paper sheets from best to worst.
The CD versions are also, by their very nature, "rarer", and require more effort; you have to get a hold of the physical CD and digitize it yourself, whereas ripping something from a digital platform often is just a few clicks away.
I can only speak for myself here, but in my experience, putting some effort into digitizing something gives you more of a personal 'bond' to it, and makes it more likely that you'll give the release some proper attention. Library releases are not only checkboxes on a spreadsheet, but individual works of artistic expression.