Your instance is it’s own thing and will only push data that’s from communities created on your instance to others.

However, since your instance will have limited users, it will consume fewer resources and your browsing experience would be faster.

I’m not sure of where the limits are on the pushing side of things. If people from a lot of instances are subscribed to a particular community in an instance, there is a lot of outgoing data from there. This is something I’m curious about.

In effect, not really.

All the communities you’re subscribed to will now also have to push all their updates (posts, comments, upvotes) to your server, even when you’re not interacting with Lemmy.

As someone else mentioned, it would only be efficient once you have a decent (hard to pinpoint) amount of users on your server.