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.
