It is an excellent idea to give money to people who don't need it. That's the whole point of UBI. There are some other good arguments in other replies, so I won't reiterate those, but add another: peace of mind.

Suppose you make $50K and support a family on that. At that level you don't need UBI, but you don't have any buffer. You get a UBI cheque every month, but the increased taxes take away most of it. Now suppose something comes up at work that makes it intolerable. You know that it's going to be pretty difficult to prove that to the unemployment office, so without UBI you'd just grin and bear it to keep food on the table. But you see those UBI cheques coming regularly so you know they won't stop. You now have the freedom to quit your job and look for another one without starving your children.