Looking at our squad we have six wingers: Aubameyang, Pepé, Saka, Martinelli, Nelson and Willian. I think that's too many already, even if some of them could be used in other positions too.
Benrahma is a decent player, probably not top 10 quality but he could play in Premier League. At 25 it's very much up to debate how he'll develop over the next few years. It makes him a potentially attractive punt for clubs like West Ham or Brighton, who can afford to give him the playing time and don't stand much to lose. I think it makes him a pointless target for us though.