Earlier I updated the Homer and Charry ahnentafel entries with citations to church and vital records indexes. Each of these citations noted what the index stated about where to find the original record. I write as I research. This indirect citation is thus an interim step. If an index provides a volume and page number, I put it in the working citation. If a book cites gravestones or vital records, I quote the book's information in the footnote. This is a useful habit for the "res-write" process,[1] that is, synchronized research and writing, because it stores that interim step. The next research step is to use that index information to find the original record.
Sadly enough, if I am working on my family, I sometimes go no farther than the indirect citation.
The credibility of my work product would improve if I went to the vital records (or their microfilm copies) every time. As genealogical standards state, "The original is the most authoritative source."[2] Not much room for argument there.
[1] This is a term I coined for my speech "Research and Reporting the Right Way -- Together!" It reminds me of Research-Write/Right, which I like.
[2] Board for Certification of Genealogists, The BCG Genealogical Standards Manual (Washington , D.C. : Board for Certification of Genealogists, 2000), Standard 21, pp. 8-9.