One of the big reasons for UBI is the belief that an individual can better assess their own needs and wants, and procure them more cheaply than the government.
This is partly a moral/philosphical stand - the tension is between giving individual freedom in the form of money, or giving freedom via paternalistic methods where the government decides what is best for you. It can be argued either way.
I do agree it would be wise to have systems in place to trickle the money in daily instead of monthly - this would help your concern of people blowing all their money at once (but not prevent them spending on what was most important to them).
I also think that just UBI will never be enough - there is a place for targeted government support - healthcare, addiction (part of healthcare), mental health (also part of healthcare).