I don't support any UBI policy that leaves anyone economically worse off compared to existing welfare. In fact I would expect people to be reliably better off after you factor in secondary benefits such as a reduced time burden upon individuals (time can be a scarce resource when you're poor) and increased ability to prioritise your own needs. The last thing poor people need is fewer resources.
I also don't support any UBI policy that attempts to supplant programs which address disability as opposed to straight poverty.
In my mind the essential benefits of UBI are:
• Less fraud. It's much harder to game a system when everyone automatically qualifies for it.
• Less stigma. It's much harder to be ashamed by reliance on a system when everyone automatically qualifies for it.
• Less disincentive to earn more. Most welfare programs cut out out after you exceed a particular income threshold, so many people have an incentive to keep their income low. (Or to lie about income.)
• Less complexity. It shifts the burden of economic rebalancing away from welfare programs (written by politicians and administered by gate-keeping bureaucrats) and towards a system that already exists: progressive income tax. While everyone qualifies for UBI, high earners are progressively, functionally disqualified by having the UBI clawed back in higher marginal income tax rates.
• Increased mobility and increased incentive to migrate to areas with lower cost of living.