To do a 1-1 peg properly, the government must be willing to let you exchange in both directions at almost the same rate.
So, if they want to peg usd to silver at 1$/ounce, they must be able to give you an ounce of silver for every dollar, and vice-versa. This would require the Treasury to have 102,058,283 metric tons of silver in reserves, or about 1/4 of the mass of all humans, or about 200 times the total world reserves of silver.

Then to peg bitcoin to silver at one bitcoin per ounce, they would need to be able to produce up to 3.6 trillion bitcoins if and when people exchange their silver. This can't work.