Average play time doesn't mean much in terms of actual game quality and value for your money. I've played games just to go through them, get the story and play the sequel, the one that's actually good.
Average time played is not a good metric because people on both extremes will skew it heavily, like any average - people who bought the game but never played it, or people who play it way too much. It also depends a lot on the game. On an okay-ish game that has a +/-20h campaign will be pretty easy to munch through just to check it off, but one can easily abandon an okay-ish game with 5-10 minute matches after a handful of hours.
I understand the point you are making in regards to average time played, but surely the people who, quote-unquote, play the game way too much, enjoy that specific game very much? Please note that you can also see the median playtime on the abovementioned website.
Is that a common practice? I once accidentally bought a "standard" version of a game instead of the "ultimate" on my Xbox One and had to deal with a couple of support people to refund my original purchase in order to get the other.