Combat Adventures New Vault Block 1.21

The Vault Block in the 1.21 update could be revolutionary, this block creates an opportunity for tiers of loot and loot scarcity/value making Minecraft progression more streamline and balanced. Instead of taking on trial spawners at the same trial chamber over and over till you get lucky with a great drop; players can take on multiple trial spawner to get keys, then take the keys to get a guaranteed unique and valuable piece of loot.

The idea of vaults being opened once per player fixes the "all elytra being taken before everyone can get one problem" and enforces exploration to find more vaults. Instead of grinding found vaults, or getting to much good look to fast, in addition to farming gear.

This is all great, but to make the benefits of the vault block work in game the loot has to be unique and valuable like tridents, elytra, or the swift sneak enchantment. What make these items work well;

The items all have niche uses(that make them unique) that are incredibly useful in their own way. & you can only get them through the designated place or method(can't get them anywhere else). The use also shouldn't be accomplished with another block. Getting enchanted iron helmets is a bad drop...

1. It has no niche use

2. actually not more helpful than its counter part 

3. Can get them literally everywhere !!

4. Every other helmet does practically the same thing !!!!!

This post is not strictly a call for specific blocks but an outline of what does and doesn't work, in my experience. Thanks: )