I said something similar -but not in these exact words. - what do you mean by just added commentary?
I do not use these big data tools on a regular basis; however, I tried it out on a free trial from Spark, and I found it very complex and cumbersome to use and imprecise in what amount of area is needed to generate a chart - . Imo, When data starts to data include a larger number of properties not similar to the subject, it can become misleading - but it can also show a more general trend, which always should be checked against your own local market, the comps you use for your subject,t the listings and pending activity.
I hope that helps - in other words, if a chart with a larger data set shows an increasing trend but the listings similar to the subject are showing price reductions and longer days on the market and the sales that are comped in the last quarter sold for less, the trend affecting your subject market is not matching a larger trend.
I am not a big data expert, I am a market expert in my area with over two decades of appraising - not saying my perspective is better than others but I have had a good track record so far - best of luck to all in this challenging environment.