It's going to be incredibly necessary in the long run. Decentralized means some proportion of important communities are going to be on servers that will eventually be shut down for various reasons. Not everybody who's running an instance now will run it forever, but there may be communities with important conversations that folks will want to preserve.

Mastodon has account migration and Lemmy community migration should work similarly.

At first I thought this was a great idea. But need to understand a bit more about the security implications for those that subscribe and post to the communities that want to do a move. It's one thing to trust your credentials to the host server, but quite another to implicitly trust the community mod who wishes to move. How would the old posts migrate? How would integrity of the constituent posts be preserved? How easy would it be to inject comments into to historical posts and republish them on the new, official, server? Could you be held liable (whether officially or through reputational risk) for posting content that wasn't really yours? Maybe there are good mechanisms to maintain integrity of data? I'm just not sure what they are.

I think there may be implications to this that are not obvious.

Happy to have these concerns assuaged, of course!