I have used a lapidary roller to flatten precious metals for jewelry use and the principle is similar but the device is made quite differently.
Now I don't know what this particular device was designed to do, but I know what I've seen one almost just like it used for.
In the late 1960s, my next door neighbor ran a lucrative harness shop out of his barn. His name was Red Meeks and he was well know around Churchill Downs.
He had a gizmo similar to this that he used for several things.
One was to roll wet leather strips into a uniform thickness.
Another was to roll braided leather laces into flattened braids.
And the other use he had for it was to compress layers of wet cardboard and roll them to a uniform thickness. He then used a wadcutter and a mallet to cut out card wads for shotgun reloading.
He had several "tables" for it that enabled it to roll out differing thicknesses.
I never asked him what the name of it was or what it was originally designed for. Like many things in a working shop, he might just have "adapted" it for these other uses.