With this perspective, there's no distinction between micro and macro contexts for money. It's all a unit of account for how the economic output of a society gets distributed. Transferring money from one group to another is the exact same thing as transferring real goods and services, except that the recipient gets to choose what slice of the economic pie to receive (by paying for it).
One perspective on UBI is that it is compensatory payment to those harmed by factors which enable greater aggregate economic performance at the result of concentrating returns in a narrower group and driving down real wages for the masses.
Like, it's not a moral matter, more like an accounting identity. People who have money are owed things, and the debt can be resolved by exchanging said money for the things the money-owners want. This works not because people who own money "deserve" to get things, but because this is how society has decided to keep track of who should get things - that is, by paying for those things.
Two things:
(1) opportunity for wealth building is only one, of many, reasons for BI, and (2) It is certain that for some portion of the population, additional income will not be sufficient for notably better wealth building. But its equally certain that some portion of the population that would net benefit from BI is held back solely by short-term resources.
People who win a fortune by the lottery often lose all their money shortly afterwards, even those people who intend to save and invest it. The reality is that some people are better than others at turning capital into gains through investment. There's definitely luck involved too, but Buffet knows how to buy a business, be its steward, and generate growth, not just for his business but for the economy in which it resides too. Simply investment in diversified mutual funds is not the same thing.
If you pick a typical poor person and give them $10m, they probably won't have the education or discipline even (to know how to) live off investment proceeds, much less grow the amount substantially. (See the outcome of most lottery winners)
That being said, basic income is talking about something different entirely, which is giving a lot of people a little bit of money. I think that could have a positive effect, although for all we know it may be transitive and only lasts as long as the money is being supplied. I think the question is whether the money helps people lift themselves out of poverty, and educate themselves or their children so as to enter the middle or upper class.
I think you could have expressed your first post more clearly -- I assume your point is that transferring wealth from one person to another in a particular society does not make that society as a whole better off. On a micro scale this is correct, but it may in fact make society more wealth if it leads to a more productive population in the long term. But it could just as equally lead to a less productive population. We'll have to see.
But total global wealth is probably not what the aid-givers are trying to maximize here. In fact, I think pretty much nobody is ever trying to maximize that.
2000 calories to a starving person helps them alive, which translate to more wealth they can generate later on. 2000 calories to fat people is worth much less, if not harmful. Capital is just an abstraction of goods, and certainly their usage will have vastly different effectiveness depending on situation.