iBonds ETFs make it easy to scale bonds across multiple client accounts. Not every bond trades every day, so when setting up client accounts with individual bonds, you may be getting different CUSIPs. Managing the cash flows, combing through bond inventory to stay fully invested can be a full-time job. Even when outsourcing to a fixed income separate account manager, not every client account meets the minimum size, which typically can be $250,000 or more.
In contrast, iBonds ETFs allow for a more consistent experience. All clients own the same CUSIPs. Since iBonds ETFs trade on an exchange like a stock, they are block tradeable and limit orders can be used.