Because this makes it easy for non-web-savvy creators to get paid, at regular intervals. It establishes trust & familiarity for the users giving money. It's als

Because this makes it easy for non-web-savvy creators to get paid, at regular intervals. It establishes trust & familiarity for the users giving money. It's also a good way to minimize transaction fees if you're supporting many creators - from what I remember Patreon batches many small donations into one large transaction.