Imagine we have a UBI, and we do all kinds of other smart things -- end the War on Drugs, establish Bismarck-style national healthcare[1], all that.
Let's do a thought experiment.
What happens when Alice blows all of her UBI on Lady Lee Vodka and Oxy. Nothing left for rent, food, the rest. Nobody else in the picture to help: no relatives, nada.
If we look at UBI as the only social assistance program, Alice dies on the street.
That's the reality, and we need to accept that.
Alternatively, we would need some sort of "backup" reserved for people that are not capable of caring for themselves.
Maybe something like restarting the mental hospitals that Reagan closed in the 80's after Geraldo -- and the rest of Our Friends In The News -- ran wild with the scandal of how awful those government-run mental hospitals were, with the end result being that a bunch of mentally ill folks got chucked out on the street.
Now, I don't know what the answer is. I really don't.
My concern is that I see a lot of people talking up only the benefits, and not in any way addressing the failure cases.
[1] Yields better results than single-payer, and is better at controlling costs.