Cutting the bureaucracy I agree, but replacing benefits with UBI doesn't work. It's universal, so everyone gets it. From the richest tycoon to the poorest. So everyone would have an extra £12k in their pocket. That will be noticed by the industries where demand massively outstrips supply like housing and so rent and house prices are likely to go up massively. So the poorest end up paying more for the basics but with less of a buffer because what they used to get in addition to help them is now something everyone gets.
I'm not saying UBi is a bad idea, but you can't use it as a replacement for benefits. As old people get a state pension should we remove all the price concessions etc that they get?