The pro UBI arguments completely miss the 2nd level effects - the predators will come out in droves and the less intelligent will be conned into long term contracts that consume their entire UBI. UBI is a gift to the wealthy - it gives them a huge pool to steal from.
Possibly, but that sounds like a problem which could be solved separately, perhaps with stricter laws about what constitutes an onerous contract; we need not discount UBI entirely because it causes some problems, since the problems UBI causes might be better than the problems we have without UBI, and the problems with UBI might be easier to solve.
If the issue of predator treatment of consumers were addressed first, a large amount of the pressure for UBI will evaporate. The poor are poor due to predator capitalism, not due to any lack of skills on their behalf.
It might be that UBI is politically potentially possible, while the other issues are not politically viable to solve in the present situation. Politics is the art of the possible.
Being poor isn't a lack of intelligence, it's a lack of money. No doubt a few people will get conned out of their money, but for the majority it would be a net positive to have more money at their disposal.
That will absolutely happen sometimes the question is how common it will be vs how many other people will be able to use those resources to get themselves into a better situation.