sometimes an IOU of a bitcoin is worth more than an actual bitcoin and you need services such as ripple or traditional banking system. If you don't currently have the need to keep assets in IOU form, don't do it.
Why should they be more worth?
The only reason I see that it can be more worth as its possible to use for lending. If I want to lend my BTC/money I prefer to control that by my own and not by the monetary system. Or try to tell your bank that you dont allow them to use your balance for lending. They simpyl cannot as the whole system is based on that model. You need to put cash in a bank safe to get there. But in countries like Italy or Spain cash tranfer over 1000 EUR (Italy) or 3000 (Spain) EUR is already forbidden and there a pretty high fines if you break that laws.