It ignores all NSFW communities. I'm planning on adding a switch for that, but if you really want, you can change nsfwFilter property in local storage through devtools. all is for everything, none is for no NSFW and only is for only NSFW communities.
Sometimes it fails to follow a community. Maybe it's because community is not yet "synced" to the instance you logged in from. Don't know much about exact reason, because I'm new to lemmy from the tech side.
There is also a planned feature to exclude whole instances. Currently only possible with editing local storage.
I wanted to focus a single community at once and make a sneak peak of it all which is some numbers, description and top 10 posts. This way it's less likely to accidentally skip some cool community. Also this shows you random ones and not some type of list so you're exposed to more niche ones.
Anyways I think lemmyverse is also cool, just a different approach to discovery of new communities.