That rather depends on the alternatives. We could employ plenty of managers that could get us regularly in the top ten but we can't buy our way any higher so have to try and weed out those with potential. If Arteta is highly thought of by those he has worked with and has a growing reputation he will be a gamble worth taking.
We've got it all to gain and little to lose.
We've got plenty to lose, we can't afford another managerial fuck up and end up changing our manager a dozen games in to the season, the chances of which increase massively when you take on a manager with zero experience in the day to day management of a team.