The article mentions "Industrial IoT", but applications of time-weighed averages in industry are much, much older than the term IoT (or "Industry 4.0"). It's the cornerstone of recording data from industrial controllers and sensors, and as a functionality, it's built into most of the relevant industrial tooling (e.g. historians[0]). Support for time-weighed average and other means of retrieving and analyzing such compressed data is included in core industrial protocols like OPC Classic and OPC UA.
As the article says, it enables data compression - but the article is mistaken (or simplifying too much) by saying data points are retained only "when the value changes". In typical implementations, data is retained when rate of change changes (i.e. first derivative). As long as the data points fit on the line, you can recover them all from line's end points with linear interpolation.
There's some more sophistication involved in this, too: for example, when configuring data archiving, you may set up "deadbands" - basically defining how thick the interpolated line is; data points that fall on this thick line will be considered as if they were perfectly centered, and not recorded. On top of that, most systems also track metadata like "sample quality" or "engineering units used" - there are rules specifying when to record a sample if its metadata changed.
All in all, it's an ingenious approach, but it comes with certain consequences:
One - what this article is about - when data is stored in such fashion, you need to use time-weighed aggregations (average or other functions) to compensate for some (usually most) of original data not being recorded.
Two, this technique assumes a single, continuous process being recorded. Imagine you're using a "smart scale" to record your daily weight. After a month, you give that scale to your partner. Right there you introduce a discontinuity; any data query that overlaps the period between your last stored (not measured, but stored under compression) measurement and your partner's first stored measurement, will return nonsense.
These two caveats sound obvious, but I've seen industrial project getting both of these wrong at some point.
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