Inflation is not a tax: there is no government entity that collects inflation payments.
Not having any money is worse for the poor than having a basic income, even if there is inflation. The market has no direct incentive to serve those without money. The alleviation of widespread human suffering due to poverty and the massive increase in the general utility of the market to humans clearly makes UBI the moral choice.
Inflation does benefit debtors: with money being cheaper, loans are easier to pay off.
It is not good, nor a benefit.