Do you ever wonder why all of the price curves look similar when Bitcoin has huge gains or dips? It is due to inflation/deflation. When looking prices in USD, what you are looking at is a value typically using the coin and Bitcoin as the trading pair. This being said if the value of BTC increases while the price of ETH remains .048 BTC, the dollar value of your ETH will also increase by the same % as BTC. However this curve is modified by the performance of the coin. If the price compared to BTC increases while the price of BTC also increases, you will see a bigger rise in the coin you are looking at.
I hope this is helpful!
