Since Lemmy doesn’t have a lot of content yet, I primarily browse all. Since there are a lot of active communities in all that I’m not interested in (different language/NSFW, etc), it would be really handy to be able to block them from the ellipsis menu. Right now you have to go I to the community and find the block option there. Similarly for users.
In addition to what others have said about filtering certain posts/users from the ellipsis menu, you can also preemptively filter domains/instances/users/keywords in the settings:
Settings shortcut: Settings > Filters
Very cool, thanks for the tip!