I guess it depends... Some may want to preserve machines for historical significance or whatnot.
For me the functional aspect is more important. I mainly use old machines to create demoscene productions. In my case it doesn't matter that much whether I use the 'original' or a clone, as long as the results are the same.
Although, at certain extremes, having the 'original' as reference hardware is a good thing. I do think it has to work on the original hardware first and foremost, and only then do I worry about clones or emulators.
There is quite a big pitfall in only using clones or emulators, and never testing on the original hardware. These clones and emulators may have various quirks and bugs that the original hardware does not, or vice versa. So there is a real risk of writing code that works fine on a clone or emulator, but not on the original... or vice versa.
I suppose the catch-22 here is that I don't know how accurate my hardware needs to be until after I've finished the demo. Which effectively means I can't take chances, and need to have original hardware available for testing.