In addition to Adrian Bruce's answer, there are many processes that are done in the background of indexing. Here is an interesting article from FS Wiki on Waypointing. https://www.familysearch.org/wiki/en/FamilySearch_Wiki:WikiProject_Waypointing
Indexing is simply a way to create searchable text so a researcher can find the image with their ancestor's name. Once they have done that, they will be able to see the image and the other information on the films.
By the time they get out into the Historical Records, they definitely must have a place and year - otherwise it's a waste of space, as you suggest. I thought I'd seen it written out that the place and year are added after the indexing, as what's termed meta-data, because the whole of a directory has a common place and year. (That's a bit moot with places in directories, so I remain slightly concerned with that idea).
@Dave C Smith
I am "Tagging" this (General) 'Question' of yours, to the 'Group' being "Indexing Chat", in this "Community.FamilySearch" Forum; so that, the members of that group can answer/assist you; and, hopefully provide some perspective.
That makes sense. Thank you so much for explaining that. After indexing hundreds of names from pages without location or dates I couldn't see how it would be helpful. But I kept telling myself if these directories weren't helpful FamilySearch would not be posting these projects.
I would still agree that many of the projects have proved not to be too useful, with such vague detail. I frequently come across indexed church records that show no parish and, admittedly more rarely, are not even added to the correct collection - so there is no clear idea of the location of the event concerned.
Even in cases where there is a link to the actual image, if these are restricted (e.g. can only be viewed at a FHC) this is generally of no use to those of us affected by FHC closure at this period in time.