What does it mean by saying "Little more convincing is the argument that the shipowner controls the
The context is:
"Rix, J.’s view that this would undermine “the integrity of the bill as the key to a floating warehouse” is unconvincing, since the key concept was developed to protect merchants against insolvency, not fraud. Little more convincing is the argument that the shipowner controls the form of the bill, since even the most sophisticated bill is unlikely to be proof against forgery by a sufficiently determined fraudster."
I am confused. Does it try to say the argument is not convincing or the argument is more convincing than the former one but still is not convincing enough?