I interpret application as being about the package of documents you submit in order to be considered for a job or for admissions. Whereas graduate-admissions is about the admissions process in general. (This is based on my observations of how the tags have been used so far, it doesn't say anything about this in the tag wikis or excerpts.)
- How does a prospective applicant fail to qualify for RAship, but fit the bill for TAship?
- Weaker chance of admit if classmate has already been admitted to graduate program?
whereas the following are explicitly about the application that you submit for consideration
- Is there a standard medical fitness certificate format for applicants to European universities?
- Is it acceptable to list unpublished papers in a PhD application for computer science?
Along the same lines, in job-search there are some questions that aren't about the actual application, and some that are.
It's a subtle distinction, which is probably why it's not applied very consistently. But I do see this difference in their usage at least some of the time, so I don't believe these tags are redundant.
(I also do find these tags to be reasonably useful in their current state, i.e. even though they are not applied perfectly. So I would use the distinction above to tag new questions, but would not be in favor of re-tagging old questions en masse.)