Because that's effective against inflation

I hear that thrown around a lot, but what does that even mean? I mean, zero percent interest rates indicate to the market that we've eliminated scarcity (as the markets would be investing/consuming as if there are unlimited resources available)... ahat does a negative interest rate even mean?

This is my problem with politicians/economists/media outlets who talk about zero, or near-zero interest rates (or anybody who believes that the interest rates can be effectively centrally planned), is that they are proving that they don't even know what an interest rate indicates. It scares me that we have people trying to control something of which they don't even understand the basic principle of.

Why do interest rates need to be low?

A Negative interest rate means HEAVY risk and calamity.  Or at least, perceived risk and calamity.

Imagine for example, Angola.  It's the most expensive city in the world to live.  Largely because of it's lack of saftey.  You essentially need to hire people to protect your shit.

In such an enviroment, an Angolian bank probably doesn't have to offer an interest rate, and can even mean they could charge you.

You might be able to get a negative interest loan in a case where it's expected there to be a massive deflation and then later, revaluation.  Say for example.  The Europeon union breaks up. 

A nation that has a weaker currency value, but a stronger baseline economy might end up getting a huge loan with a negative interest rate, because they know that when they're paid back... they will actually make more money then if they activly let there capital rate depriciate in value.

Or this can be done as per government policy just to force peoples hands into spending. 

Think of it like a wealth tax spend it now or lose it anyway! 

Oh and for what it's worth, a Negative interest tax rate... and outright "Money carry tax" was something Keynes was only against because making it work seemed impossible... since how could you tell how long someone kept there money.

Some leftest economists suggest barcodes on money, deducting money based on how long it's been since it was last swiped... which again is well stupid and unworkable in a real world setting.

Don't be surprised to see a "money carry" tax the minute we switch to a virtual cash system.

Such a tax though would BADLY hurt the lower middle class and poor.

Having an "Emergency" account for disasters would go from hard, to impossible and kinda dumb.

Forcing people to gamble and falling into bad times if a disaster hits.