HDR vs no HDR makes a big difference in colours to me. And if you compare compressed low Bitrate footage vs higher Bitrate there will often be artifacts or color banding, particularly in darker scenes or wherever you have gradients.

It ofc also depends on what device you are watching it on. But I would say that yes if you have a movie (made up example) that is compressed to 5gb total size vs 25gb vs 70gb for the uncompressed Blu-ray quality, then the first jump will be a very noticeable difference assuming you have capable hardware. Whereas the second one will be much much less noticeable and also come with other drawbacks that need to weighted off, e.g. storage requirements.