non-BISAC metadata read?

[pslsr]

Hello: does metadata that is NOT BISAC coded, get any placement and/or ranking, by the majors (or any publishing-type page)?
-I'm a Sigil newbie & while I've put in the 1st few BISAC codes for my ebook creation, I don't want to waste a lot of time putting in "other/more", only-potentially tag-able words.These would be routine and tag-able for ordinary sites, but maybe not for ebook publishers/distributor sites. If the pubs/distros are not even going to "see" or list (or in the end they "are" going to refuse) non-BISAC coded words, then I guess it's just do the gross-subject BISACs? Tell me I'm being too pessimistic. I have like 50 non-BISAC tags that would really help visibility & rank (I think...). Thank you.