A UBS would require a lot more government oversight: I can see lots of laws for civil servants to intepret and implemenet as to what would constitute a "basic service." Just think of rent: should a young person be "forced" to find a roommate.
As for the alcoholic father buying booze instead of food for his kids, here's the beauty of UBI. When the UBI provides basic needs for family, and the family is not providing those needs, that's a family that needs definite government intervention.
But there would not be many UBI recipients who would not need that oversight.
If someone wants to take a photography as an occupation, great. But if there are too many photographers out there, should the government really be responsible for finding jobs for all of them?
Back in the days when social assitance was a political hot polato in Alberta, the government created a ministry of finding welfare reciprients work. That ministry cost more than the benefits the recipients were getting.
The UBS, as described in this essay, falls very short in a useful social program.