>>882075Definitely not necessary. The only real advantage of the opinel in that the blade is really thin. As I see it, the upkeep needed to maintain their knives just isn't worth it for something like mushroom hunting where it's constantly getting wet.
Moreover, their blades are too thin and small to be useful for anything else. You're better off with a $20 Kershaw beater knife for mushroom hunting. Something that can take a little abuse.
Source: bought an Opinel (not the mushroom tool) for mushroom hunting. Was dissapointed.