Why processors see digital products as risky
A card processor pays you before it knows whether the sale will stick. If a customer disputes the charge weeks later, the card scheme takes the money back from the acquirer, and the acquirer recovers it from you. With a physical product there is usually a tracking number, a delivery signature and a returned parcel to argue with. With a digital product there is often only a login timestamp, which issuers rarely find persuasive.
Three features stack the risk. Delivery is instant, so a dissatisfied buyer has already received everything before complaining. Value is subjective, so 'the course was not what I expected' is hard to rebut. And many digital businesses sell through paid social traffic, where impulse purchases and buyer's remorse are common. Underwriters have seen enough accounts fail on this pattern that they price for it from the start.