Lower bandwidth for who? When images are cached on other instances, it allows two things:

• Load sharing. The original instance doesn’t have to serve the whole fediverse, but only its own users + 1 request per other lemmy instance.
• Data availability through redundancy. If the original instance goes down, the cached image is still viewable on other instances.

For a more user-friendly (IMO) alternative, altough not open source, there is Resilio Sync. The main difference with Syncthing is that you don’t introduce clients to each other; you just share folders.

When lemmy.world will disappear, that’ll be a lot of communities (and valuable information) that go with it.

they can’t trigger on the edit event as there are too many legit uses of it.

They definitely do, I’ve experienced it firsthand: I mass edited all my comments to “[deleted]” and many of them got edited back within 2-3 days. There are some reasonable explanations about buggy caches, but that’s a really convenient bug for Reddit right now.

They get edited back. I’ve been playing this game for 10 days. I edit once or twice, then delete a few days later, and there’s still comments popping back.

They’re basically the same browsers, and arguably, you’re using the better one to install the worse one.