might be a stupid question but what is the reason for a overdraft limit?
This is some kind of protection from a short-term price jumps in the market, more info will be in our FAQ.
I think your answer is wrong it should be because that's how the Bank works. This is some sort of protection in order for your card to stil have a balance on it. It's why it was called a debit card rather than credit card. Because credit card can overdraw with a high fee while debit card rejects it. I experience this once with one of my Debit card.
I think it's used in case your in the a shop to buy something and the mnx price suddenly drops a bit after which you wouldn't be able to make the purchase. With. A buffer system could decide at that moment to release that buffer so you could still make the purchase.
but we will know for sure when the FAQ is up