But isn't the point of BI that everyone has enough for their basic needs? It would seem unfair at that point to tell some people try and get charity funding (which might dry up at any point).
There are plenty of people whose basic needs are substantially larger than the average citizen. For instance, many people need expensive motorized wheel chairs, which would be difficult to purchase on BI. Currently, the state provides motorized wheel chairs to many, but there are many stories of this program being abused. It's quite possible that a charity could step in here to supplement BI to make chairs affordable, and could do better and more efficient needs testing than the state.