Thanks for taking the time to post the explanation but I still don't see what value it adds, like most statistics, TBH.xG is a very useful statistic over the course of many matches (10+). Teams generally will regress to their expected points total (derived from xGF and xGA) or within a certain range, so it can be good at identify underlying issues that are counter to a run of results.
The problem is that it can be very deceiving or misleading on a game by game basis. This of course leads people to use it in ways that it really shouldn’t be. Often times it just confirms how a match “felt” in terms of the balance of play, but it really needs to be given context for it to be useful.