On the per diem -vvs- company credit card question........

I was eating lunch with a guy yesterday who use to fly for Kelloggs.
They had a company credit card and he said that they didn't watch it that closely so long as they didn't go craxy on EVERY trip.
We currently employ standard gov't per diem - min $46 in some cities but up to $71 as a high domestically.
I eat what I want on the road (and that isn't a good thing) and still generally spend half of my allotted per diem so I end up taking home and extra $50-$100 home every trip which we wouldn't get if we had a company credit card/expense account.

I'd be interested in what the positions are in EAS on the pros/cons of this part of the contract.