I recently submitted an application for registration for a large body of work with the Copyright Office, all online. After a lot of procrastination, I was running out of excuses for not doing it.
The previous times I did it, it was all by paper submission. Online was not an option then.
There was a little bit of a learning curve doing it all online, including making a few calls to the Copyright Office to get a few questions answered. They were great, and the wait time to talk to someone was surprisingly short.
I will not delay in doing it again with the next body of work.