Do some reading on the YZF / R6 VRR swap; it's considered almost de rigeur for these older bikes. The fact remains that people have had failures with these newer VRR designs - even if it's a newer design, we ARE talking a used piece of electrical equipment that's 10-15 years old. You may have noted that one of my planned products is a plug-in adaptor to fit a newer VRR to the 4-pin harness connector without cutting and crimping, to make it easier to upgrade the VRR.
Also, fuses are meant for sudden spikes in amperage; sustained loading just below the trip point will cause overheating and failure of different components. Fuse size selection is a trade-off between protection and nuisance trips - putting a 6A fuse in a circuit rated for 5A will result in a lot of cranky people, but a 10A fuse will catch short-circuits before it causes damage. A sustained 9A won't pop the fuse, but can cause damage over time.
While fuses and VRR normally work, they are demonstrably insufficient protection under all circumstances. The purpose of my little toy is to add another layer of security.
George, Mal - thanks guys, but gently please. There's a fine line between chiming in with support, and dogpiling!