Notably missing from the comparison list is any mention of video or screen sharing, or anything to do specifically with games. These are Discord's unique strengths at the moment and they have been for a long time. With that in mind, Matrix is a "good alternative" to Discord in the sense that most other desktop VoIP or chat apps are since Discord users aren't using it for the privacy and openness aspects and want the Discord specific features and ease of use.

Don't get me wrong, I wish I could fully replace Discord with the Matrix instance I currently self-host, but there are things Discord just does better than every other app including having a bunch of features that range from meh to pretty good all in one package.