Meh, I don’t like mushrooms and really don’t like the black bean burgers and haven’t liked any other veggie burger I’ve tried, but the Impossible ones I can hardly tell the difference from cow, so … why wouldn’t I choose the impossible when given the opportunity?
So, for me, I guess the answer is that if I want a burger, I want a burger, why would I go for something that doesn’t taste anything like a burger?
One of the eventual goals of kbin is to be compatible with the rest of the fediverse and to “just work” with the rest of it. By way of comparison, Lemmy is basically just a federated Reddit, so, this is actually one of the reasons I chose to go with kbin.
From a practical standpoint, it’ll likely be a while before that becomes a reality, but I like that as a goal.
I’d say see if you can search for the instance in the search (once we’re 100% federated) and if it doesn’t work and it’s something you want to participate in, unfortunately, you’ll need to go there directly.
Also - Your kbin.social account can only log into kbin.social, you can’t use it to log into any other sites (this would include other kbin sites, lemmy sites, mastodon sites, etc…), what you can do is see content from those sites by subscribing to them or on the front page (non-subscribed)
From what I understand due to the way that Lemmy handles federation, it doesn’t (currently?) have a way to handle an instance changing its domain name and still being able to communicate or even an individual user changing their instance and retaining their comments/votes/etc… (this might be more ActivityPub limited since the way Mastodon does it still seems pretty hacky and just a work around for underlying issues).
From a website perspective, yeah, just change some settings and you’re good to go and accessible on the web, but that doesn’t mean that anything regarding Lemmy is going to actually work.