The accounts are FDIC insured and held in an accredited bank according to the website. $250k of insurance per account.
Does that make sense? I suppose technically just like your accountant could steal your money because they have access to your accounts there's some risk but not really.
If anything, you could make a solid case about a bank going out of business before anything. But all jokes aside, before building anything, security of funds is something we made sure our users feel really good about and we found a great partner to make sure your accounts and deposits are insured!