1) A file in one drive of a person (A) is shared with another person (B), person B can only view the file (is prevented of sharing/printing/mailing/copying). This can be useful for company owned documents, they can at each moment be consulted by everyone.
2) A file in one drive of a person (A) is shared with another person (B), person B can work in the file (just like A) but is prevented of sharing/printing/mailing/copying. This can be useful when e.g. people on the field need to update documents for the management at the office, preventing that this information can get out of the company.