I usually prefer looking at my profits/losses in USD rather than in BTC because Bitcoin price is usually changing so it's hard to track the profits or loss in BTC.
This is how I also look to my profits too when I trade alts but, some traders do follow the satoshi pricing and that's how they calculate their profits.
It will really just vary on what you are trying to accumulate since from the start it would be either BTC or USD. If you do look for fiat profit then it wouldnt matter if btc price or alt price would soar up or dump down as long you do see your portfolio is gaining up thats why its always important to have a tracker.In my case ive been using Blockfolio app on checking out my holdings
and ive been doing this for years and when the time i do able to gain in terms of fiat then i would definitely sell out and then re-buy when the price had gone down once again.
Rinse and repeat as long you can earn money then you're doing good.