Although I think your a wind up I'll respond anyway.
But Marv is and has been pretty much fully fit for a while due to having a decent pre-season, so much so he managed 120 minutes against Forest. And Marveaux also is not a first teamer (as yet anyway) meaning in League matches he has been restricted to 8-9 minutes. Due to a combination of these things, Marveaux can play in the reserves to sharpen up.
As for Ben Arfa though, he is a first teamer and Pardew clearly wants to use him in games. And despite what you believe, simply playing in as many reserve games as you possibly can does not mean you will get fitter any quicker, you have to space it out otherwise you'll be fucked come match day (which you don't want, as match fit or not Pardew clearly wants him involved).