Blu-ray (and above) is essential, in my opinion, to experience the full intention of the director and thereby view the film as it should be viewed. DVD compromises the quality and information of the image greatly, sometimes creating visual artefacts, weird sharpness issues and an overall soft look. Of course it demands the right setup all around to truly be able to see what you are missing. There is a lot of information in the image that you will simply never see with DVD.
At first it might be a bit of a shock. Some may find that it's "too sharp", but remember it also depends on your setup (your tv and the likes). You might also need to learn a bit about your TVs settings and what each of them does. Because suddenly, you are seeing all this insane information in the image that you are not used to, and that also means that all the little things can be seen - including if you have your sharpness setting set too high, your white balance is off and so on... often tv manufactures have standard image settings that will make your tv "pop". But they will in most cases look unnatural. That can easily be fixed though - a quick change to a "cinema mode" setting with only a few clicks will help greatly. And the next steps all depends on how deep you want to dive into it all (calibration of your tv and the likes).
There are a lot of people who hold on to DVDs because it's easy and been around for long, but also because they find the look to be "right" to them. But if you are truly a film purist, you should at least check out the benefits of Blu-ray and 4K. For one, they preserve the natural film grain, so if you like or love older films (or just films shot on film negative) then Blu-ray (and to a greater extend, 4K) will replicate that look very well. Watching a great Blu-ray or 4K disc, it can sometimes feel like watching the movie for the first time all over again.
To put it into perspective, a standard DVD has a size of 4.7 GB (gigabytes) of storage. A standard Blu-ray has 25 GB. That's more than five times the size. But it can go up to 50 GB for the larger disc. As for 4K UltraHD Blu-ray, the standard is around 66 GB, but it can go up to 100 GB. That's a lot of numbers, but just think of them as information. The bigger the container, the more information, the better quality, the closer to the actual film print/DCP. When a movie is shot today, on digital for example, you can easily end up with several Terabytes... now, 1 terabyte (TB) is 1000 GB, if that helps with perspective. I recall when watching
All The Money in the World - a two hour film - that the movie file size used in the cinema was about 200-300 GB. So with DVD, all that information is pressed onto a 4.7 GB disc.
To me, when I watch films, I want to respect the film and the people behind the making of the film. I want to make sure I watch it the best possible way I can. And perhaps I am a bit more nitpicky about it than most. Sometimes I will even refuse to watch a film if it's DVD quality or less... "But MM, if the movie itself is good the quality doesn't matter all that much. It's the movie itself that counts". I can certainly see the point in that, but I have found that the more "fuzz" I make when watching a movie the greater my experience will be...
There's a reason movie-going was an "event" back in the day. It has always been something more than just a movie. I feel like I'm taking a huge dump on the director if I watch his movie on a small smartphone screen, while riding a bus on my way to work, then pause it halfway and finish the film on my way home. Stuff like that hurts my cinema heart.
I have a 65" OLED at home with a sound system capable of Atmos. I want to make sure that whether I watch Truffaut or Transformers I want to view it the best way I can. Because even though Transformers is what it is, I feel like you haven't really watched the film if you haven't watched it with a great screen and sound system. Because especially for movies like that, it's
part of the experience to make sure that every surround element is placed right and every little bass response can be felt. And actually, there's a lot of drama movies too that benefits from a great sound system. Directors like Malick and Lynch, for example, care greatly about this. Their movies can really be elevated if you make sure you get everything that was intended into your own experience of the film. Malick's
Knight of Cups even has a title card talking about the sound mixing, explaining how important it is to view this movie at high volume.
This is a massive ass write-up, but my point is that a lot of work is put into making a movie. A small change in the color, a tiny sound in a certain scene. Everything matters. And every cinephile knows this, I'm sure. And I definitely do not think that cinephiles have not made the jump to Blu-ray because they want to sh*t on cinema. Of course not. But if you take your time to invest in a greater viewing experience, you will also be rewarded.