- there have been a lot of large-scale BI policy experiments in the past in many countries, and none turned out so well on the long term. Yes it's true that technology changes many things, but I think it should be exploited primarily to improve existing benefits (considering the criticality of healthcare and housing, two major factors of both economic insecurity and inequalities);
- I think a healthcare single-payer or public option experiment would be more impactful, because this is what is currently at stake in Congress, the Supreme Court and the coming presidential election + it's important to win many small victories in the present rather than a hypothetical large one in a distant future (any union leader would agree). Finish the job on healthcare, and you'll discover that it becomes easier to advance the cause of UBI.
I guess you're more of a communist and I'm more of a social-traitor ;-)