Reading the thread it sounds like you're honing in on the point. Carrying a roll of coins could be an offence with intent to use them as a weapon (as suggested), proving intent is a matter of evidence.
The moment it gets used in a fight, then there's both intent and also a very good chance of proving it. In fact it would be a very bad idea to use coins, because it would raise the type of charge and penalty, and reduce the odds of success of claiming any kind of self-defence - it's more likely to be argued that the person was out 'looking for trouble'.
But someone walking down the street with coins in their pocket being wrongly accused? It would be very hard to prove intent. That may not stop the police intervening, but the odds of it being prosecuted would be minimal, and of actually succeeding even less. There are circumstances where you can imagine intent being proven though. If a group of thirty men going to a football match all had a roll of coins in their pocket, I think that would be an unlikely coincidence, say.