Confusing Contractual Obligations in Patent Licensing

Maine socha tha I understand Contract, and then the paper happened. Section 30 of Patents Act, 1970 says "right to sue" for infringement can't be assigned. Fair enough, but then I read Section 70 of the same Act, which talks about the assignability of "benefits". Is it just me or is this a contradiction? I mean, how can the right to sue be non-assignable, but the benefits of patent licensing can be? It sounds like two different rules for the same thing. Has anyone else struggled with this? Can anyone explain why this is, and how to tackle this in the exam?