Seems like it should definitely not be the default sorting mechanism. It's a fringe use case at best. Most people subscribe to communities across the 'verse and their default should be "subscribed" and have 5> communities and "all" if not logged in or have fewer than 5 community subscriptions.
Ah yes, I know. I just meant the default setting for new users.
Instead of "Active" and "Local", it should be "Hot" and "Subscribed" (or "All"). I think anyone who spends enough time to get used to it here quickly realizes they should change their profile settings.
It's a feature of federation. Each instance can have it's own communities, even with the same name. So there could be hundreds of "no stupid questions" communities out there.
Picking 'local' let's you see the feed of your instance. Picking 'all' shows you the feed from all.
On a well-fedorated general purpose instance, it likely wouldn't matter, like lemmy.world. however, it would be useful if
Your instance is dedicated to a specific purpose, like lemmyNSFW and some programming/art/starterk oriented instances. Then you can view all the instance content without going into specific communities.
You instance has special moderation rule. You might want to take a break from wider internet, and only enjoy well-moderated content on your instance.