What should I use it for?
In case of posts - should I downvote things that I don’t agree with? Or things that I don’t want to see in my feed (posts with low amount of votes fell more to the bottom)? Or things that I consider harmful/stupid/younameit?
In case of comments - should I downvote something that I don’t agree with? When should I use this button in case of comments. Or maybe I should not - cause what’s the point, actually?
No, a downvote is not a comment.
I disagree. If you ask me, it is a comment in form of a data point. Comparable to the “thumbs up” you can do in real life. I think almost all people would say that this is a form of commentary. Or applause, and “booo” on the other hand. They are not literally words, but communication is more than just words. Even on the web. Another examples would be the new kind of emoticons a user can flag a post/comment on Reddit, similar to Discord.
Edit: Or just make a tiny little thought experiment. Lets assume I just downvoted your comment above, for any reason I might have. Is that really no commentary at all?
I think it’s no commentary at all, since there’s no content in your "comment’.
But it is also not nothing, is it? The person using the downvote button has a reason to do so. It’s not purely random. It is a reaction, and it is visible to everyone, including the creator of the comment.
Yeah, but what does it mean? What meaning has this downvote?
According to most users on Reddit and here, it means the voters disagree with you, and don’t recommend others to read what you wrote.
You are right that a fully detailed explanation is lacking, but it also doesn’t mean literally nothing.
See that someone downvoted my comment above? The person doing thought that my comment wasn’t okay, I guess. Whatever the reason might be, it wasn’t something positive, but something negative.
Wouldn’t you like to know the reason? Wouldn’t this knowledge make discussion worth more?
Absolutely! Answering with a text comment is always better than just voting without commenting. Though voting still isn’t literally without meaning, and still is useful.
Not sure about always. Wouldn’t an attention seeking troll posting something controversial enjoy tons of comments instead of downvotes? I guess a protocol is to upvote your favourite dissent instead of commenting?