Years ago an acquaintance of mine told me about a bad experience he had had with some cell company's customer service. It seems that the contract he had received had said that he would be charged for data service at the rate of ".02¢/kilobyte". (This was in the very early days of cellular data, so prices weren't well established, and I'm probably not remembering the correct number, but as you'll see, that's not the point.) When the bill came, he found that he was in fact charged 2¢/kB -- 100 times more than he expected. He called to complain, but was unable to communicate to the customer service agent that, correctly read, .02¢ = $.0002. The agent apparently looked at the notation ".02¢" and read it as "$.02".
One can understand the psychology of this. The notation ".02¢" contains two indications that the value 2 is to be multiplied by 1/100: one is given by the position of the decimal point, and the other by the use of the cent sign instead of the dollar sign. But if you read those two indications as redundant rather than independent, you get the interpretation used by the agent (and apparently also by the person who wrote the contract).
So I would suggest that the "$10 dollars" thing is not as benign as it appears. Mathematical notation is not supposed to have redundancies in it, and we should not get used to seeing them there -- particularly when money is involved.