~snip~
Is not a bitcoin it's 100 in USD he can only get this 0.0015166451808599BTC if he buys bitcoin at this rate $65,935.
And how did you actually get 31 dollars? He gains are only $1.5 when he sold this 0.0015166451808599BTC at $66,935
This is right.
Since $65,935 to $66,935 has 1. % something increased, that $100 will become 101.something (lets say 101.2-101.5 usd)
It just means you only gain 1 dollar something. And that just become useless because the fees are quite high than your profit.