What If There Was A Huge Tax On Currency Trading?

What if currency traders when making money were also helping the wealth of a nation? What if currency traders were taxed on each trade and that money was used to kick start third world nations and emerging markets? What if we used this money to build water reservoirs and water filtration plants or what if we used it to build sewer treatment plants and hydroelectric power plants?

What if we used the money to slow down or defeat AIDS, Malaria, Yellow Fever or stop disease? What if we used the money to help promote children