Actually, I sort of understand why the median was used – it can tell you quite a lot of things – but only in conjunction with the minimum and maximum data points, and number of data points used.
Sure, it will churn out a number, but if you can’t compare that number to the highest price (max) versus lowest price (min), then you have no idea whether the prices are skewed towards the bottom (ie a few very low prices pulling the median down) or positively skewed (more prices at the top pulling it up). Having the number of data points also allows you to calculate the other two ‘averages’ – mode and mean – which will give you a much clearer picture of whats going on over time.
Stuff like this is a bit of a bugbear for me – I spent many years of my life teaching Basic Math and Statistics at community college – unfortunately many people (and I don’t include the posters on this forum 🙂 ) don’t know the differences in the three averages, so just take a number (any number) as Gospel.