If whispers is not designed for bot use, then wouldn’t it make more sense to make that clear in the API documentation? What is there currently is a simple mention of the spam classifer, information regarding how to send whispers (at least using commands), and a list of chat bot whisper maximums (by status of user, known, or verified). Nothing about that context implies that you are most likely not going to be able to send whispers; what that strongly implies is that you most likely will be able to.
Also, I wouldn’t necessarily expect Twitch to disclose everything about how spam whispers are determined; like I wouldn’t expect to see their list of regex expressions. However, I would expect things such as needing to have a user send a whisper before being able to send one back be listed. And I’m not even sure if this is true or not (I have seen it suggested in other posts), which is, of course, why I posted the original question.