The importance of different cameras is all to do with what they can do, as tools, and how they make you feel and operate when you use them.Rob C
From my perspective the important difference is largely how differently they can make you interact with what you encounter ..... and how they prevent YOU from being the 'tool' in the equation.
In a world of 35mm SLR style cameras (film OR digital) with their horrid little looken-peepers how many functionaries these days are remotely aware of the joy of the waist level finder or the ground glass? In photographing people flatteringly how useful was the waist-level finder at operating the device at an appropriate elevation in relative comfort? Apart from the Rollei/Leaf/Sinar reflex and the Sinar M, I know of no other digital reflexes which offer such convenience.
DSLRs and rangefinders are all well and good for a reactive approach to photography whereas the ground glass and waist level finder with inverted and reversed viewing provide a level of separation which affords a contemplative and meditative pathway to considering the world before you trip the shutter. That single difference has a massive impact on how a relationship between photographer and subject engage, and that difference is magnified immeasurably when you add the element of the live subject, which is the case with the vast majority of pictures of people. And 'people' photography must be a two-way street of communication. (I do subscribe to the Roland Barthes' concept that the corpse is a living representation of a dead thing, but I doubt a corpse is really too concerned with how the photographer functions.)
So, I guess I am saying that the camera itself and how it manifests itself on the shoot is an significent contributing factor.
I am also completely convinced that I shoot very differently when I know that I have film loaded which only sees the world in black & white — or colour. Black & white requires a completely different mindset to colour. Different lighting ratios. Different lighting patterns. For me at least, the fact that the digital image will be colour which can be rendered as monochrome at will tends to negate a lot of the thought processes that go into managing the formulation of an image. Contrast by colour is a very different kettle of fish to tonal contrast. Being aware of, and controlling, tonal merges before I shoot draws me deeper into the intricacies of the image, for example, opens choices of remedies ranging from lighting to the use of coloured contrast filters. (Have you tried to walk into a store lately and buy a Yellow-Green filter?)
An exaggerated example of being in a mindset for the materials being used would be shooting Infra-Red.