Only taxing one thing, whatever it is, doesn't produce a very good tax base. People can avoid doing the thing that's taxed and do more of things that aren't taxed. This not only distorts the economy badly but it also means that the tax rate has to be fairly high to compensate for legal tax avoidance, creating even more of an incentive to avoid the tax.
This might work for a broad consumption tax like a VAT because it's hard to avoid consuming things. It kind of works for property taxes, but tends to seriously penalize people or businesses that require more property (such as farming). There's no way it could work for this kind of tax.
This tax is particularly bad to implement at such a high rate. It is effectively a tax on saving money so you can avoid this tax simply by not saving money. Not saving money is very easy. You can either consume wealth as quickly as you earn it or hold other kinds of investment assets instead of money. So there would be an immediate and rapid death spiral -- as the rate goes up, there's less and less saving, hence less and less revenue, hence a need for a higher and higher rate, and so on.
If you think about it, there's really no need to save money. For many people, they spend most of their income very close to the time they earn it, so they are already avoiding this tax. Wealthier people tend to hold most of their money in non-cash forms such as real estate, boats, airplanes, stocks, and so on. So they would already be avoiding this tax. Who would be paying it?
Quickly, the government-issued currency would simply be abandoned. The government would be printing money that nobody would accept, as happened in Zimbabwe.