To be honest I think it's really weird to dismiss Benzema based on the fact he never played with this French team. The team he played with was very disfunctional. I believe he would of fit this team more than Giroud who's to say he wouldn't of clicked and scored a wealth of goals.Giroud wasn't in his prime either and he was still more consistent, they roughly have the same age. Benzema has simply not been good with France, he wasn't particularly good when Giroud was his backup and Giroud would routinely outperform as a starter or coming from the bench.
I have always liked Benzema and I rate him highly but people are totally misguided when they talk about France, Benzema wasn't good, he should have been benched way before the Valbuena story and Giroud deserved his spot. Giroud is a lesser player at club level, there is no discussion about it but with France he has always been the better performer.
Especially considering he can bring exactly what Giroud brings and much more.