This would at least be very useful for maintenance of typo fixes in file titles, maybe elsewhere, as well (in some kind the opposite of T171155 I guess).
Generally, when files are renamed (technically moved to the new name) they are not deleted under the old name, but a redirect will be created. So, if there is a typo fix, the wrong name will still be found with an according search. But if one frequently is searching for new files with the same mistake the redirects of the fixed files are interfering.
Examples from the wild:
- avaition for aviation: https://commons.wikimedia.org/w/index.php?title=Special:Search&search=file%3A+intitle%3A+avaition
- illistration for illustration: https://commons.wikimedia.org/w/index.php?title=Special:Search&search=file%3A+intitle%3A+illistration
- The spelling of Potsdam is slightly unusual, it’s easily miswritten as Postdam (alas, there is a village with this name in Belgium): https://commons.wikimedia.org/w/index.php?title=Special:Search&search=file%3A+intitle%3Apostdam+-belgique
On the other hand there may be cases when it could be useful to search only for redirects.
Edit: The examples above are from Commons only, but this would be useful elsewhere, too: Searching for possible impacts of an issue in dewiki it was necessary to find lemmata with parentheses containing templates commons and commonscat, but the results show quite a lot redirects with parentheses (very probably created by page moves) making it harder to look for the issue impact: