Gold in a vault, it must be there at all times, or that should be the demand from the public. There should not be a "the gold does not feel good" day. However, now I think about it...
Thieves can steal from the vault, it is not 100% impenetrable. Vault-owners may seek to maintain the "illusion" it is by replacing the gold, but gold may not be there some days.
This is why notes are signed by individuals and not in the name of "entities". Business Entities are the disguises that malevolents use to prey upon individuals.
Hm, I was thinking more along the lines of "illusion in a good way", as in thieves stole the gold of a customer, let's replace it for him, cause it was our fault it got lost.
You are quite right that the trust that this helps building will be abused sooner or later, but my point was more that at least short term, "gold" is more reliable than "workhours"
One ounce of gold of purity x replaces another similar ounce, and when you got it in your hand you got it in your hand. Workhours depends a lot on who works, and so on.
I mentioned earlier, an "1 Hour" voucher will probably evolve to not be a work hour. It is just intended to be a valuation of someone being present. This has another usage: security.
I have to think a bit more about this, but still it seems to me "gold not stolen from vault" is far more reliable than "human being being able to do work of type x" both at given time.
Understand that the Value staked is never actually redeemed except in default. Issuers would redeem the voucher for some equivalent to "1 hour" job. They may prefer to give gold, or ?