After pondering this for a while, these are my thoughts. I think that the fact that it is hand cranked rules out its use for wire recording. To ensure accurate recording and playback, you would need a consistent speed, difficult to obtain by hand. As for rewinding recording wire, I would think that would be done by simply reversing whatever mechanism was used to move it past the recording heads in the first place. Manual typewriter ribbons autoreversed when they hit an eyelet at the end of the ribbon, so you wouldn't need a device to rewind them. There were ticker tape winders, but they were clockwork, and later electric. Again, the requirement for constant speed. If it were a spool filler of some sort, it wouldn't need to wind back and forth. The combination of no requirement for a consistent speed and the ability to wind back and forth would argue for it being part of a film editing device of some sort. I agree that the rollers as they are would not be suited to this, but perhaps in their original condition they were polished so as not to scratch the film. Also, I think we have to allow for the fact that we may be looking at this upside down. That seems like a lot of exposed gearwork to have sticking out above the work surface, and the spool holders (for lack of a better term) would be easier to work with if the openings faced up. Just my thoughts.
