There is one BIG problem with your technical accuracy dogbrain, I didn't technically say they used the roman coin system. I said they used it for the basis of the D&D coin system. Using it as the basis no way infers it was an exact copy of the original, just the inspiration for how they did it in 1E and 2E D&D.
So your knowledge of coinage is impressive, your application of it to my statement is totally unwarranted.
like I said, not only have I studied the Roman coinage system, I own a couple of dozen coins with many different roman ceasars, or other symbols, stamped on them. So they are not foil thin, as another poster seemed to infer they are, but they are very irregular, both around the edges, and on the facing, plus the stamp is no where close to being centered. Apparently, this irregularity was the roman way to keep their coins from being shaved, much like the rough ridging on the quarter and other coinage. Overall, they are smaller in diameter and slightly less heavy, than the US dime, no matter if they are copper or silver. I do not any any gold coins, but I have seen and handled the 4 my wife's uncle owns, and they are generally the same as the copper and silvers that I own.
So that is why I use a 100 coins per pound standard. Factually accurate enough for me.