There's a difference between random one-time gifts of $1,200, and depending on the largess of a single patron every month in order to feed yourself. The B in UBI stands for basic, not luxury, and it's unclear that those dependent on UBI to survive would be able to save money.

UBI will help the destitute, but if the person holding the purse strings, be it a billionaire philanthropist, the government, or your employer, and you're dependent on that to survive, that gives that entity power over you.