Because UBI is a permanent cash handout while this is a temporary measure that only consists of bond purchasing? Unless you think UBI should be high interest monthly loans, I don't see why you are coming up with your conclusion.
Why would the loans be high interest? Fed interest rate right now is almost 0%. In some countries the interest rates are below 0. Why do banks have the special privelage of barrowing at this rate but people don't? Its a scam!