Imagine your UBI money become $500 in a day or transaction fees suddenly raise to $10, that'd be disaster for people who barely make a living

Perhaps the money should be given to people who actually deserve it, the majority of the population, the working class. (people who actually give up lifespan at a exceeding rate to serve others)
It works when all the people have food water and shelter, and the city`s are more self sustaining and housing. So wait what are we suppose to do let a few create the supply while the rest of us slave for it?
Fuck that, everyone should make the supply at the same rate, then enterprise if they want to.
To be fair, Welfare system already achieve what you said.