When GCI re-profiled the helix in 2015, it was no longer needed so it was disabled. Even before then, it was just being trimmed just ever so slightly to help make the helix more comfortable and less wear and tear on it.
Well, before those new trains on the SFNE Mind Eraser, it was known as the smoothest SLC, so it's pretty high up there. I wouldn't say it's butter smooth, but it's certainly way better than your standard Six Flags SLC, that's for sure.