What if we do away with all taxes and impose only a Consumption Tax?

The transition would be brutally unfair as everyone with savings would essentially be double taxed.

It's super regressive and allows tax free investment growth, so the rich will get richer and low/middle class forced to consume less. Despite exacerbating income and wealth inequality, it might reduce CO2 through reduced consumption. I can't see how it would ever be worthwhile to switch, but maybe if you started your society that way you could continually tweak it.

https://taxfoundation.org/consumption-tax-policies/ [..] Consumption taxes provide a major source of revenue in OECD countries. On average in 2019, consumption taxes made up 32.3 percent of total revenues in OECD countries. In Chile, 53.1 percent of total revenues were from consumption taxes while in the United States, consumption taxes accounted for just 17.6 percent of total tax revenue.

When measured as a share of GDP, Hungary leads OECD countries with consumption taxes measuring 16.2 percent of GDP. The United States is again at the low end with consumption taxes raising 4.3 percent of GDP.[..]

I think a Usury tax would be better. It would put less of the burden on the poor since they don’t take out loans, and it would be easier to administer as the lenders would handle it.

There wouldn't be enough revenue as not many people have Tuberculosis, formerly known as Consumption.

Wouldn't this be quite regressive?

Taxes are not just used to raise revenue, but are also used as a way to control behavior.

Any transaction that is taxed is disincentivized.

By disincentivizing consumption as compared to saving, you would reduce spending and therefore the velocity of money. https://en.wikipedia.org/wiki/Velocity_of_money

By reducing the velocity of money, you would trash the economy.

TLDR: Money would sit in banks. Anyone doing anything for work that wasn't an absolute necessity (i.e., things with inelastic demand) would take a huge hit. Everyone would be worse off.