we all who watched italian football long enough know how was inzaghi; he was totally, totally skilless footballers yet scored more goals than 95% forwards in the world history just by using positional play.
as such, sometimes playing position smartly is often enough to offset technical skill, even if isla and asamoah are somewhat limited at beating players they could still be useful at penetrating the flanks with positional play especially when countering, it is reason enough to try them as wingers and in case of asamoah it's certainly better than seeing him doing his futile stepover thousand times already as lwb.