I was with you till I read the word TAX. Get a clue, people have had enough of that in the old economy.
Let me clerify :
**NOTE : This tax is an insignificant number. If you make a transaction, within X amount of months, you will not be taxed. This is also based on income size.**
For an extreme example, You can't let 1,000,000 Aero's sit in an account for years without making a transaction.
The "Tax" will stop hoarders from hoarding the currency. There are plenty of currencies you can hoard and hold onto to for infinity, but that does not grow the economies or create market depth.