[UweSchmidt]

>That money won’t dissapear. It’ll get spent or invested (either directly or indirectly by a bank if saved).

Only in economics 101 would the bank need deposits for loans. In the real world there is no upper limit on money that wants to be invested, just a lack of feasible investment opportunities.

More fundamentally, governments want to stimulate the economy at all costs, so interest rates are near zero ("please take our money and create jobs") and plenty of attempts at subsidizing industries have been (and are still) made.

Since you can't quite force economic growth, startups etc., at least you can have money in circulation.

So, money in the bank, like money under the mattress, is bad for the economy. So, the tax cut may infact be bad from an economic perspective.