but what is the cost? and why only 50%? the exchange should be trusted to put all 100% of your coins without risk, so as the exchange "hacks" continues the people will not trust to leave the coins in the exchange for long time, and the day trade is obstaculized by this, why cant you guarantee 100% of the bitcoins? with cold storage is not virtually impossible a hack?
We actually cover all costs for our clients. In regards to the 50%, there are numerous reasons behind this. To name one, any funds held in Xapo's insured enterprise vault aren't instantly retrievable, and we want to ensure our ability to process large withdrawals in a timely and predictable manner.
We're also not saying that we only guarantee the safety of 50% of client bitcoins, we're saying that we only insure 50% of client bitcoins. Safety and security are the backbone of our firm, and any bitcoin company in general.
Deposit insurance?
I think it is unnecessary
Understandable, but quite a few Mt. Gox creditors may disagree with you on that one.