From Reddit, not BOC but general Bandcamp related:

Artist perspective: I’m a solo artist with no label. There is no extra support from Bandcamp here. When you place an order for a record for example— I get the order notification immediately, but then I need to pack and ship it.

If I’m busy, then that might take a few days. Sometimes you might be ordering from an artist who is out on the road touring, so they cant process orders during that time.

Its usually much more efficient if you are ordering from a label that has warehouse operations and can get stuff out pretty quick.