Why do we have them? It seems really inconsistent that one wiki has them while the other has them in the character’s page even though we run both of them.
Yeah, I think at some point in the future (not right now) I'd like us to reconsider which of these characters actually need battle subpages. I don't like splitting things into subpages, because people land on the character page expecting to find battle information, so for some characters like Napstablook I don't think it makes sense to have a separate battle subpage. But for some characters I think it'd probably make sense to have a separate page. We have searches like "flowery battle", "flowery fight", "jevil fight", "knight battle", "mike fight" etc. that might mean these pages might need battle splitting.
I think the issue of In Battle pages was that they were a relic of our pre-fork days before we split off battle forms (like Mettaton EX) to separate pages. I think the idea was that we could shove everything about any battles onto those pages, and it spread out to other boss fights.
The problem with merging them back together, however, is that the resulting page would potentially be extremely long to read comfortably. This won't be a problem for pages like Napstablook or Mad Dummy, but it will become very apparent on pages such as Sans and Sans/In battle, both of which are very long pages in their own right. There isn't an easy solution to this problem outside of picking and choosing which characters actually deserve subpages.
We may consider making subpages for characters with complex and/or multiple battles, such as Rouxls Kaard and Knight. This will, of course, coincide with the decision to merge some older in-battle pages and may not happen until things slow down here.
I'm actually working on a potential solution to a similar problem: group fights being spread across separate articles covering the same battle. You can see an example of this here, where I cover the group battle against Susie and Lancer on a separate page. You can read more about this proposal on this post, though I do plan on making a full post at some point when I'm not busy with other things.
I think this topic is a little more nuanced. Minibosses definetly don't need them, but I don't think some regular bosses do as well. For example: the Titan in Chapter 4 doesn't need one since it is barely a character and there isn't much information about it besides its fight.
However, there are also cases where the fight is extremely complex and would benefit from being covered in a different page such as Sans, the Knight, Rouxls Kaard, Flowery, maybe Pink, etc.
With Tenna and Flowery having sub-pages for their respective speech patterns, I think we should 100% have a discussion about standardization of sub-pages.
I genuinely forgot about this
Also I agree