The UBI crowd takes theses studies and uses them to say ‘UBI works’ or ‘UBI can work’ even though it’s not UBI.
That’s a bit disengenuous. Of course people acknowledge that economic policy is difficult to experiment with.
People serious about UBI talk about phasing it in over a long period of time, in lieu of “experiments”. For example in Australia we already have refundable tax rebates (I’m sure everyone has these I just don’t know what they’re called), all you’d have to do would be to introduce a $1,000 refundable tax rebate and increase that by $1,000 each year until you get to a reasonable UBI. If, along the way the data showed deleterious effects then you could correct or discontinue.