I actually don't care if a particular detail in one game doesn't end up canon. I still think they matter, and I would say most game developers seem to agree with me. There are tons of things in lots of games that might or might not end up as canon later. Just because only one character in Tekken 6 ends up canonically winning according to tekken 7 doesn't mean seeing all the other character's endings was pointless. They were still fun and gave some insight about their characters, even if they didn't end up winning. Even if there was revealed a Fallout 3 official canon where the main character didn't kill everyone in Tranquility Lane, that doesn't mean that whole subquest was worthless and unimportant.

You (Bright Shield, that is) seem to be extremely focused on what is canon and not, and it seems to me that you think the only content in a game that matters is the content that later ends up canon (but excuse me if I mistaken about this). I'm not going to argue against you on there being only one official canon, because I don't actually disagree with that (unless something crazy is going on, like the writers revealing that both stories happened, but in different dimensions or whatever). I just don't think canon/noncanon is that big an issue in games where you can play things out differently each time. Even if not canon, these things often show "what if" scenarios in whichever games you're playing, and even if "Character X" canonically didn't get a chance to do "Action Y", you still learn something about that character's personality. You learn what he would have done if he was put in that sort of situation. In a sense, we get to know this character better than the character knows him or herself. Even if that isn't part of the canon.