My internet routinely goes down a few times every month (thanks Xfinity) and usually at the most inopportune time. Can anyone explain how the offline launcher works? Any pros/cons?

I had the same problem with the internet. I turned on the local license server, or whatever it's called, and Houdini worked without the internet, connecting to the internet only on a long-term basis, I don't remember if it was a week or a month. The problem only occurred when the internet was down at that moment, so it's a pretty rare occurrence.