I think the concerns with UBI are (1) it takes away the leverage of a labor force to organize and strike for better benefits or economic conditions, and (2) following the block grant model, can be a trojan horse "benefit" that sets the stage for effectively deleting systems of welfare support that have been historically resilient due to institutional support and being strongly identified with specific constituencies. When the benefit is abstracted away from a constituency it's easier to chop over time.
I don't exactly know how I feel about those, but I respect those criticisms. I think the grand synthesis is that UBI exists on top of existing safety nets.
In practice there are a few strong local unions (NY teachers, ILA (eastern longshoremen)), but in general it doesn't help those who are no employed. (Also when was the last general strike that achieved something ... other than getting general strikes outlawed?)
... also, one pretty practical problem with UBI is that cost of living varies wildly. And if it depends on location then people would register in a high-CoL place and live in a low-CoL place. (Which is what remote work already should be doing, but many companies are resistant to change.)
In theory it makes sense to have easy to administer targeted interventions, because then there's a lot of data (and "touch points" - ie. interaction with the people who actually get some benefit), so it's possible to do proper cost-benefit analyses.
Of course this doesn't work because allocation is over-overpoliticized, people want all kinds of means-testing and other hoops for people to jump through. (Like the classic prove you still have a disability and people with Type I diabetes few years have to get a fucking paper.)
So when it comes to any kind of safety net it should be as automatic as possible, but at least as targeted as negative income tax. UBI might fit depending on one's definition.
... maybe? it depends on how it's implemented. (and that depends on the legislative purpose.) the usual equality vs equity thing comes to mind. (negative income tax has probably the most desirable properties for this as far as I know.)
I don't exactly know how I feel about those, but I respect those criticisms. I think the grand synthesis is that UBI exists on top of existing safety nets.