Reasons: +UBI Robs from the rich to give to the poor... and give back to the rich a little bit. "Billionaires will die without UBI." It's simply not good nor true to the intent of BI to give money to people who already have plenty. "But means testing will cost so much!" Actually means testing if you earn less than C.O.B is not very expensive, and giving UBI to everyone is very very expensive. Something like 6-12x more expensive. (PGI with C.O.B. of 24k would cost $800B annually, UBI would cost 3.6T)
+aside from giving to the rich for no good reason, UBI causes an increase in commodity prices anytime the fund is issued. This is like having a highway turn at 340* and being very incensed when people crash because they are going too fast. There is no way to avoid a spike in commodity prices when giving UBI out and especially when you give it out to everyone, why? because everyone getting more money devalues money (for a brief while). See: Supply of Money (M0, M1, M2...) and the Kuwait attempt at UBI from 2011. They blamed their ministers of commerce for the crashes on the 340* turn, of course.
+ Value Added Tax is not good to fund B.I. of any kind because it's likely that this "luxury tax" will hit a lot of the recipients of the B.I. The Roosevelt Institute did a study on a potential UBI to "grow the economy / gdp by 12% annually" which is cool to consider, but one of the key assumptions is that a funding method like a VAT would not hit the households getting UBI. Plus, their study does not do UBI, just B.I. of different tiers. If the VAT hits the consumers who get the B.I. then it's taking with the left hand what was just given with the right.
+ In short: Don't give back to the rich. Don't make a VAT that taxes the poor inadvertently (B2B vat is the only vat we could support then it seems). UBI would cause commodity spikes during currency issuance and that's unavoidable, but the amount of issuance is proportional to spikes so: Only give B.I. to people below a Climb-Out-Bound. Give them ( C-Earnings )/ 2 to incentivize their working out of poverty.
Example: Climb-out Bound 24,000. You earn 12k, the government gives you 24-12 = 6k, and now you're at 18k. The closer you climb out of poverty, the less you get, but you cannot get more than 12k, and if you work you'll make more than someone not working. Make sense?
Because what people fail to remember is the Federal reserve act of 1913 and its FEDERAL mandate that employment be kept at a running maximum (keep them ponies movin' raw hide). +Progressive Guaranteed Income does not violate the 1913 Federal Reserve Act, but actually works with it.