> "Besides that, asking any government to take money from the people, run it through the giant bureaucracy machine, and magically produce a net benefit to the people is both logically impossible and naturally never going to happen."
Your logic is sound, but you've misunderstood something crucial.
Where does money come from? In short, money is created in one of two ways; by government spending and by bank loans. All money that exists in the rest of the monetary system was originally formed in one of these two ways.
From the viewpoint of the worker, money exists only after something of value is created, after all that's how we get paid, we do the work then the money ends up in our bank account.
But in reality, money exists before we earn it. The money in my bank account and your bank account isn't 'ours' before it's someone else's.
The way that money is spent into an economy has a large role to play in the the quality of life of a society that is based on money as a medium of exchange. Some of the ways the money is created can be destructive to the economy (for example, when mortgage values increase faster than wage values), whereas other ways can boost the activity of an economy (for example, healthcare spending).
The role that the banking industry plays in the creation of money has the potential to undermine the social good that UBI could offer, but I don't want to detract from the main point, and the main point is this; understanding how money is created is very useful in understanding how to get the best out of the systems we build on top of money.
UBI organised by a government can just be a different way to spend new money into the system. Aside from the usual effects of inflation it doesn't have to involve your savings or earnings at all.