Just look at all the social "safety nets" that many European countries have. That money then gets relabled "basic income". Pensions, unemployment benefits, paid sick leave, child support money, etc...
For people who are working full-time and don't get anything at the moment, the taxes would have to be increased slightly to offset their "basic income" on average, so maybe with a low wage you would have a small gain, with a big wage you would have slightly less than before.
The advantage could be a massive reduction in bureaucracy. The disadvantage in Europe at least is that many people prefer perceived "fairness" over efficiency, i.e. they are more worried that someone who "should not get that money" will get it than they are worried about their social systems wasting money and peoples' time.