Reminds me of another thing that I didn't mention at the time, but there is utility in being able to search for any and all bangs. It's admittedly not very helpful for the curation type of search (show me good posts with this attribute), but it is extremely helpful if you already know what you're looking for.
Imagine if you're trying to find a specific post you've seen in the past. You may remember it has bangs, but it's often close to impossible to determine the specific subtag that was used, or what any individual tagger determined the style to be at that time.
Or let's say I was trying to identify who Momiji is in post #5945646. (The astute among you will notice this is not actually a hypothetical.) My search would start off with something like blue_archive, green_hair, hood, fur_trim, and bangs. As-is this search would've gone fine and I would've found my character. But with the absence of bangs I now need to pick a bangs style for this search. I don't know, I guess they look like blunt bangs? Lo and behold she is now no longer in any of the search results.
This is just one case out of many that will be adversely impacted by this change going forward.