MADRID (MarketWatch)—A six-thousand year old bubble, ”shiny Bitcoin,” and something that no self-respecting central bank should hold in reserves ever.

That was Citigroup analysts, laying into gold in a note that came out a day ahead of Thanksgiving, as the investment bank opened the debate on gold’s value ahead of a crucial decision by Switzerland on whether the central bank should more than double its gold holdings.

The “Save Our Swiss Gold” campaign aims to force the Swiss National Bank to hold a fifth of its assets in gold within five years and prohibit the bank from selling gold in the future, as well as repatriate any gold overseas. Organizers accuse the bank of mismanaging the nation’s wealth property.

While gold bugs are hoping for a “yes” vote, most analysts don’t see that happening. December gold GCZ24, , which traded around $1 lower to $1,195.60 an ounce on Thursday in electronic trading, with U.S. physical markets closed for Thanksgiving Day, has seen a choppy year, which has left prices more or less flat.

In the note, Citi’s global chief economist, Willem Buiter, said the Swiss vote doesn’t even make sense. “Requiring a central bank to put 20% of its balance sheet in any single commodity, even if that commodity had meaningful intrinsic value, represents a highly unorthodox and risky investment strategy…” he said.

And it’s also a custodial risk—holding all of a nation’s physical assets in one place and preventing the SNB from ever selling gold again would in short make those holdings worthless, he added.

Another reason central banks shouldn’t be dropping a chunk of reserves into gold? The price is volatile. The below chart shows gold on a nominal basis, which show its money values in different years, and real value, which adjusts for price levels in those years. As far as real prices are concerned, if someone had held on to gold in 1971 and held it up to 2013, the annual real return would be 4.3%, said Buiter. “Reasonable given the riskiness of the asset.”

Citigroup/Kitco/Bureau of Labor Statistics

Gold is like Bitcoin: Buiter says gold is unlike any other commodity, and the only thing that comes close to it is Bitcoin and other virtual currencies. Gold is costly to extract from the ground and refine to a degree of purity, it’s also costly to store and has no real use as a producer good, and other alternatives are out there for industrial uses.

“Gold has become a fiat commodity or a fiat commodity currency, just as the U.S. dollar, the euro, the pound sterling and the yen…are fiat paper currencies and as Bitcoin is a flat virtual currency,” said Buiter. “The main differences between them are that gold, like Bitcoin, is very costly to produce, while the production of additional paper money has an extremely low marginal cost.

Count up the deposits of commercial banks with the central banks, which together with currency in circulation make up the monetary base, as fiat money, then the incremental cost of fiat base money creation is zero, he said.

As for gold bugs, until the risk of serious inflation is taken out of the medium-term outlook for big the U.S., the U.K. and other fiat currencies, gold could be attractive, despite how much it costs to store it. Of course that assumes if paper or electronic fiat money loses its value, gold will keep that value.

“Even though I view gold as pure bubble, that bubble may well be good for another 6,000 years. Its value may go from $1,200 per fine ounce to $1,500 or $5,000 for all I know. Investing a vast amount of money in something whose value is based on nothing more than a set of self -confirming beliefs will make for an exciting ride,” said Buiter.