In 1.9 we can not say easily that somebody may visit course, but does not actually participate in it. The capability moodle/course:view is used for both
- the user can view the course
- the user can participate in the course
In 2.0, a new capability moodle/course:participate can be used to explicitly specify the second (ie actual enrolment in a course).
Normal users in a course would have both. Users like managers and so on who just need to see the course would only have "view".
We can get rid of the old hidden role assignments field completely.