As someone who uses both Reddit and Discord quite a bit, I can definitely see the latter eating a lot of the former's marketshare, especially in communities for

As someone who uses both Reddit and Discord quite a bit, I can definitely see the latter eating a lot of the former's marketshare, especially in communities for entertainment related topics like gaming, TV, music, etc. In the case of r/LoL it's replaced TeamSpeak, and for quite a few other communities it's replaced IRC or other chat systems, but a lot of subreddits and old school forums have been replaced with Discord servers too. For instance, many speedrunning communities are now primarily focused around Discord servers, as are communities for the Mario RPGs, the Luigi's Mansion series and most game mods/fan projects. An awful lot of communities focused around YouTube and Twitch personalities have made that jump too. So while the article may have not given the best example, there are definitely a lot of instances where Discord has replaced, or at least significantly hurt the activity of a subreddit.