What you don't understand is that when you are dealing with a government agency enabled by legal tender laws, that very valuable ounce of gold goes for only its face value. Under the Utah law as written, if you want to pay a state tax with gold, that one ounce Gold Eagle is only worth its $50 face value to the state. That's all you'll get, even if today's gold dealer value for that coin is closer to $1500.
This is why that provision of the law needs to be replaced. It's a trap.