I seldom downvote anything. When I do, it’s generally because I think the content is overrated, inaccurate or otherwise problematic and needs its upvotes to be annulled. On a very busy network, that can be a valuable feature. As quiescent as Lemmy is right now, it probably won’t be an issue for awhile! I’m leaning toward “no.”

To play devil’s advocate, various UIs still show the downvote button as they’re not smart enough to know it’s disabled. (I’m browsing with wefwef right now and I see the button, although I receive an error toast if I click it.)

If the protocol has a way to signal to the client that the feature’s disabled, then this is just a bug in wefwef. If disabling of downvotes is proprietary to the Lemmy UI, however, then it’s kind of clumsy of them and there might be an argument in favor of leaving features enabled to promote a better UX.