The same reason why you might browse r/all or r/popular on Reddit. If there’s nothing new on your subscription page, you can carry on doom scrolling on local.

Discovery, and instance specific content, where the instance is topic focused

What’s in local depends on your instance. It’s pretty good on mine because it’ll give me stuff that’s relevant but not top tier interest.

I’ve been using local to find new communities that look interesting or if something shows up that I haven’t subscribed to.

Local is showing you all of the content submitted onto the “local” instance, which is the instance your account resides on. I browse locally on my Mastodon account to see what other members of the instance are up to. Still on Mastodon, the home feed is going to be people that you have followed (subscribed).

Basically, I use Local if i’m feeling like browsing just the instance and to connect with people only on the instance. I use Subscribed if i feel like browsing just the content i’ve subscribed to. I’ll use the federated timeline (on /kbin this would be “All” which i imagine is the same on Lemmy? not sure) if i want to cast out the widest net possible. With local and federated timelines, i can find more people to follow or more groups to subscribe to.

So, Subscribed shows only your subcriptions, Local shows only your instance, and All will show content from around the fediverse.

i hope this makes sense

It makes sense if you are on a specific server. Feddit.de is mostly all about German speaking stuff. So I have a good oversight over good memes, news and discussions.

Why not both? Local and Federated are useful for discovery, an unfiltered (and unalgorithmed) look at the world. If that’s not your thing, stick with Subscribed.

I browse local and all occasionally, to just see things I am not specifically looking for or find new communities that are somewhat active.

Also less so now, but like a week ago the content would dry up a little fast on subscribed.