What is the point of the myths tag? We have tags like poetry, short-stories, song-lyrics, and oral-tradition, where the tag conveys something about the medium, e.g. a song lyric is meant to be sung. But I don't see the point of the myths tag. A myth could be a short story, or oral literature. Could we get some clarification here?
There are a lot of people who are interested in mythology and knowledgeable about it. That we have a Mythology SE website going fine proves this.
Thus, the myths tag serves as a signpost, so that people who know a lot about mythology and want to answer questions about it can find these questions on this website.
On the Mythology Stack Exchange, people ask questions about "The Myth of Hercules" without specifying which Myth of Hercules they are interested in. So answers on Mythology need to, among other things, break down the different versions of the myth.
When it comes to oral literature, things are a little bit different. You can ask about "motifs" which are essentially "tale types": a way of categorizing all of the different versions of a story floating around in oral tradition.
Myth is not a tag we should use on this site because it really is a genre. For example, when it comes to something like Norse mythology, the term "Norse mythology" is unclear. Are you talking about the Christianized version of Norse mythology recorded in the prose and poetic eddas? Are you talking about the oral tradition that we have no real record of? Or are you talking about modern adaptations of Norse mythology?
One of the things that defines questions on Literature is that people usually read the books they ask questions about. I think this leads to very good questions. A broad concept such as "myth" and "[culture] mythology" encourages people to ask broad questions, which then need to be answered with a frame challenge. If we can, we should guide people in the direction of working out the frame challenge aspect of their question themselves.
Not having a myths tag is a very good way to get people to think about the fact that there are multiple versions of myths, and to get people to state whether they are asking a comparison question or a question about a specific version.
Let's say you have a question about Norse Mythology. You try to tag it with norse-mythology, but you realize that the tag refers to Gaiman's adaptation. (Or we rename norse-mythology to gaiman-norse-mythology to make this clearer). So then you're trying to figure out what tags to you. It might take a bit of thinking, but you should eventually have to decide whether you want to ask about the Prose/Poetic Edda, Gaiman's adaptation, both, or neither. And your question will be improved because of this.
Myth is not an easily definable topic; like a genre, it shouldn't get it's own tag.
An answer to this question referenced the fact that a Stack Exchange exists about the topic to support the fact that myth is a field and that it should get its own tag. But if you look at the mythology meta, you'll see that they had, and still have, a very hard time defining what mythology actually is. We already decided that we shouldn't have genre tags because genre is too hard to define. The same should go for the myth tag.