ZFS Replication - What's the Difference?

I had been using R-Snap Shot like backup mechanisms for customers of mine. I tried ZFS replication instead, and it doesn't have to go through and stat those millions of iNodes. It just barfs the whole stream of data from one machine to the next. The data took about 18 hours, I think, to replicate from machine A to machine B. That was long before I had written a tool like Syncoid.