The process often changes when a goal is scored though, which means that the raw statistic isn't as valuable as it appears.
Lots of managers are the type that will instruct a decent attacking team to stop doing it upon taking the lead. So you might have loads of first half chances, score the 7th one, then drop in and defend it. You end up conceding late and end up with a 1-1 draw. The xG stats say that you should have won 3-1 but that doesn't tell the truth about the game and how it was managed. The xR was only 3-1 because you took so long to score the first, you might well have scored the first chance on offer, and then defended that. Identical strategy but one looks better for you on the data because your strikers missed a load of chances - but if they'd not missed the first, the other six never happen.
The statistic doesn't allow for a game to be changed by a goal, and it is therefore quite misleading, which is what I thought the point Nobody (Towelie) was making was (rather than a more simple "only the result matters" one).