Well, not really, we use math actually! Once you link your main spending account, ChangEd analyzes your transactions and makes transfers (based on your round-ups) to your personal FDIC-insured ChangEd account.
ChangEd makes transfers when your accumulated change reaches at least $5 in roundups. We never withdraw more than $10 in one day in case you go on a spending spree and a ton of roundups occur.
Here's an example: