The link works for me–the device in question appears rated for 600VAC, and as such it would suitable for protecting a 120VAC line. In fact, it would be over-rated for such use in most cases and as such might not be as “practical” as a fuse in either of the 5x20mm or 3AG formats that are typically used for 120VAC applications
Under normal conditions, there is no appreciable voltage across a fuse; that only happens when they blow open to interrupt a circuit. Fuse voltage ratings exist to indicate the maximum circuit voltage that a fuse can be depended on to interrupt. Further discussion on this and other fuse-related topics can be found here.