By the way, in signal processing that’s an example of an IIR filter, but that particular filter is also referred to as an exponential moving average (https://en.wikipedia.org/wiki/Moving_average) and is a really key tool in statistical process control and other kinds of “industrial” mathematics (https://en.wikipedia.org/wiki/EWMA_chart). It has effectively the same purpose — remove fine detail (“high-frequency noise”) from a time series.