Based on the latest market prices tracked on TCG Stacked, Fishing Gear is worth about $13.02 USD for a regular copy and $10.72 USD for a foil copy
The closest I could determine was the Semitt Falls, one of the game's first true dungeons and the only one I could find that had a clear waterfall in it (obviously), even though it lacked the crystalline formations on the walls
Alternatively, you can just collect them for the gorgeous art, not to mention Stitch with his cute little earmuffs
Occasionally the Behemoth will dart to the outskirts of the arena, hunch over as its eyes ignite, and begin summoning small comets from portals above him
Even if you are unable to leverage Cloud when playing with the Buster Sword, being able to draw cards and potentially cast spells for free is a great deal for connecting with the opponent with combat damage