I get what you are saying an maybe I'm just a bit old fashioned but I do find Arteta's selections a bit strange.
Granted I know that he has played a decent amount of minutes this pre season but is yet to start a game. What I find strange is that three different players have started before him and none of these players are natural left backs. And that's with Zinchenko still to come back into it.
Perhaps he is just experimenting with it but something to me just doesn't seem right with Arteta in regards to Tierney. I just don't see him being anything more than a bit part player.
Does that benefit him long term for Scotland? I don't know it doesn't seem to have impacted him so far.