There's the question of whether or not it will be spent appropriately, which raises the prospect of whether or not there are a class of people whose economic decisions ought be made for them. Or rather, what additional classes of people exist meeting that criterion, as we already hold that children, the senile, and various handicapped individuals cannot see after their own affairs.
I guess another solution would be to earmark some amount of the funds for rent or provide vouchers for housing or other services.
There's also the matter of windfall wealth to corporations or countries. Dutch diseaase, resource curse, etc.
I'm not making this up. This was his existence for most of his life. He would see his weekly/monthly/whatever BI check as a lottery.
There are many people like him. They would not, in any way, spend the money appropriately. I firmly believe that anyone pushing for BI has never met anyone like my brother.