Carlos, it’s a good point that if link contracts subsume the functionality of consent receipts, why bother with consent receipts?
The short answer is that the concepts arose in two different communities, with two different goals. Consent receipts were developed for privacy and regulatory compliance, with work focused at Kantara, while link contracts were developed for semantic data interchange requirements with work focused at the OASIS XDI Technical Committee.
My own feeling is that in the Sovrin ecosystem, all data sharing will be moderated by apps and agents forming link contracts, and thus that we can focus entirely on link contracts as you suggest. Does anyone else feel differently?