Now with the bitcoin value rising so high, obviously the alts are comparatively at very low in terms of bitcoin invested.
Lets suppose when invested a certain alt was at 1 dollar, and now it is at 5 dollars. That is a huge profit percentage and perfect time to cash in, BUT its value in bitcoin is still less than the value you bought it for months ago.
What do you do now?
It is sure confusing at first when you are in profit in terms of dollar but you are at a loss in terms of number of bitcoin. For me, I measure my profit in bitcoin because my intention is to make more bitcoin. I disregard the dollar value because I am positive that in the future it will go up. If I just think of just sticking to bitcoin and not buy any altcoin then I would have more money compared to buying an altcoin in which its bitcoin value go down so I would have lesser amount of bitcoin and in return, a lesser amount of dollar.
But then it would depend on the person how he will measure its profit because maybe his intention is to have more dollars so even if the amount of bitcoin goes down but his dollar value goes up then he is still in profit. It depends on the point of view of the person because what if he doesn't intend to trade with bitcoin but with altcoin vs. fiat so it is just right to measure the profit with the base currency he is trading and in this case it is fiat.