You can transfer money from your bank that is used to pay your CC bill (I just confirmed this with a $10 transfer, it takes "1-3 business days"). I think the 0

You can transfer money from your bank that is used to pay your CC bill (I just confirmed this with a $10 transfer, it takes "1-3 business days"). I think the 0.25% extra interest they are offering is reduced marketing expense (general advertising but also things like getting an extra 1% for referring/being referred).