When I first looked into Lemmy I thought picking an instance confined you to that instance. I think a lot of new people don't realize that isn't the case.
It's definitely a new concept for people. I've been on Mastodon for a while so I'm already used to the idea of multiple instances
I think over time more people will figure it out and it won't be so confusing. Like how people intuitively understand that if you have a Gmail account you can still send emails to people on Outlook