I still don't see how UBI doesn't cause inflation enough to offset any benefit(in the near term ie before robot job apocalypses).
This isn't even a bad thing from an economic standpoint. Capitalism has the problem where wealth tends to accumulate upward naturally (rich get richer just because they're rich and have a bit of financial sense) and eventually starves itself of demand. Re-injecting cash in the low end keeps the economy moving despite this natural tendency. UBI has the advantage of low administrative overhead too, so more of the money gets used on goods and services. Also, unlike Welfare there is no perceived disincentive to work.
That said, UBI has its problems. Prices at the low end are likely to go up simply due to lack of workers. If you have UBI why would you do backbreaking manual labor all day for minimum wage? To really work well it has to be paired with increasing automation of low end jobs to offset the labor imbalance, otherwise you end up with inflation as people are forced to pay higher wages to fruit pickers, fry cooks, etc... in a competitive job market. Or more likely, those jobs will move overseas at an increased rate to countries where the labor market is skewed towards employers and they can pay people well below the value they generate.