I see it as the opposite, actually. They will pay you for a robust product: one that works for them. They have no care for the technical minutiae of your implem

I see it as the opposite, actually. They will pay you for a robust product: one that works for them. They have no care for the technical minutiae of your implementation, because they're just trying to do actually interesting things, with the help of your product. This is the customer perspective.