Definitely not. Even Colonies, the most efficient VP cards by cost, require more coins ($11) than they give VP (10).
I'm going to argue the other way. Yes, coin tokens en masse are inefficient if that's your entire economy; they're harder to get than other sources of $. Spending 8 coin tokens for a Province is not good unless you are doing Scrying Pool/Candlestick Maker or Merchant Guild superturns.
But in any other deck, whenever you hit $7 (or $6), a coin token is worth 3VP (or 1.5VP) for you because otherwise you would have bought a Duchy; on $4 you can get 2VP out of your coin token by getting a Duchy instead of an Estate. In Colony games, when you have $10, $9 or $8, a coin token is worth 4VP, 2VP or 1.333VP.
In most games, most of your $ is not in the form of coin tokens, in which case you can preferentially spend coin tokens only when each coin token gets you at least 1VP compared to the cheaper option. If that means you aren't spending them often enough, so that you would have a bunch of them unspent at the end of the game, you are generating too many coin tokens - but you can cash them out for <1VP each while still maintaining a healthy average.
As for +$2, take a coin token, it would be a lot better than Monument; it's terminal, so the number of tokens you'll be producing with it will be low enough to sustain better-than-1VP-each spending for the rest of the game; you also have the option of spending them on cards that aren't green.
Sure, a big pile of VP chips will beat a big pile of coin tokens any day - but in the modest quantities seen in normal games, coin tokens are better.