What does "token" mean on its own? Essentially, a small, normally fixed-size object that acts as a proxy for another object.
A token does not really do anything on its own. It is simply one small piece of a larger puzzle. If I were asking a question involving tokens, it would be in the context of a larger problem: I should use the tag associated with that larger problem instead. Stack Exchange in general has had problems with tags where there are simply too many. Users create tags that are too-specific or similar to one another. By having broader tags (but still specific enough, there is a middle-ground here) it is possible for one tag to take the place of several other tags. If you search through our meta here, you will see many questions discussing tag merges or deletions.
While tokens are essentially the same thing in different contexts, they are used differently. A token in a payment system and a token in a web application session may appear similar, but serve very different goals. One tag for both would make searching more difficult. In this case, it would be better to have one tag for payment systems and another for web applications. Note: this is a contrived example, I am not actually suggesting we need those tags.
Tokens have many potential uses (perhaps too many) in such areas as
payment systems, identification and keys. They can also work in
concert with plug ins.
You said it yourself: "perhaps too many" uses.