What's your use case? The way the blog post is written suggests that their method performs a decomposition of the timeseries into trend, seasonality, and error.

What's your use case? The way the blog post is written suggests that their method performs a decomposition of the timeseries into trend, seasonality, and error. They then create a confidence interval, that's probably based off moving smoothed mean and sd. The interface looks nice, but the math behind it is probably nothing special. It's probably worth noting that the video and sample graphs show very smooth movement. I'd garner that many of the metrics you care about will not show this behavior in practice.