I agree entirely! I see a lot of 'steampunk' thinks like this pop up on the MAKE Magazine blog (and similar) and have always found it somewhat onanistic, despite the face-value beauty of some of the pieces.
In the end, I feel that form should follow function. Making something like this look like it should be functioning in ways that it never will perhaps just serves to outline its mundanity.
(Ooh err, I've probably gone and thought about it too much again.)
I feel much worse about it when car companies or furniture makers try to make one material look like another. Faux wood, faux leather, ect. I consider the steam punk aesthetic to be purely ornamental. That the ornaments may appear at first glance to have some practical purpose doesn't detract from the overall aesthetic for me.
In the end, I feel that form should follow function. Making something like this look like it should be functioning in ways that it never will perhaps just serves to outline its mundanity.
(Ooh err, I've probably gone and thought about it too much again.)