When you use the item_used_on_block trigger in advancements, it does'nt trigger for all items:
Here the advancement for flint_and_steel and the reward function:
This totally work as intented, the player who click on a cobblestone say the message in chat, but with diamond_sword it does'nt work :
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Here the datapack that i'm using for the report :
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Diamond swords don't have any "use" functionality on cobblestone, as I'm sure you're aware. Feel free to post this on the official Minecraft Suggestions Discord, though, if you want the
item_used_on_blocktrigger to fire even if the held item doesn't actually get used.