It's simple risk vs. reward. What are your cost options for a non-warranty / gray market item versus region-authorized sale? If your savings is a paltry ~25%, it's probably not worth the risk. If it's at least 50% why not? Way more than 50% of Koetsu come perfect from the factory, and will never need to tap into warranty. Similar calculations with used Koetsu. Make the best choice for your personal risk appetite.
The distributor x dealer markups with Koetsu multiply out fast so that leaves a lot of room for gray market "bargains", and that's why this topic keeps coming up.