Interesting idea, but it's expensive to pay the other player... You loose 1 gold and he gains 1 gold... So you're actually 2 gold behind... Isn't it better if you have to pay the bank? The cards could even go back into the deck.
I'm afraid that if you pay to the bank, it's just the same effect as an extra troll.
The purpose of the toll collector is to force your opponent either to pay you, either to make another (longer) path towards the gold cards.