Yes, the coach has his reasons, he's not stupid to sign a winger when he seriously needs a striker there must be reasons for that and sometimes why coaches do that is to strengthen their depth while they chase their desired players, from my understanding about Arsenal in the transfer market they're going after Gyokeres, I don't know why they're yet to finalise the deal but I believe they'll before the league starts.
Noni Madueke is not a bad signing he has lots to contribute in Arteta's squad, he'll bring the experience he's got from Enzo Maresca to Arsenal moreover there's no need to wonder if he'll adapt since he was already an EPL player, London based for that matter.
Squad depth is much better when a coach has a number of options, and perhaps Noni Madueke's presence will make it easier for Arteta to rotate. Gyokeres was a serious target for Arsenal, and they almost landed him, so it would be much better if Arteta had a number of players at his disposal when the season starts. Arsenal's target is to win the Premier League next season, having failed to win the title in three consecutive seasons, and this can be achieved with good squad depth.
I have no doubts about Noni Madueke's adaptation, as he's a Chelsea player who thoroughly understands the Premier League atmosphere, so adapting shouldn't be too difficult. However, hoping to bring Enzo Maresca's experience is overkill, as Arteta has his own strategy for managing Arsenal.