Few days ago I decided to utilize some fraction of bitcoin just sitting in my trading wallet to try profiting from the market. Although I may profit when the profits was calculated in dollars but unknowingly I lost massively in Satoshi value. That means assuming I just kept hold of my coins I would had made almost the same value I made with the coins i bought. Many traders haven't realized this yet but just get carried away with the US value of their trades without realizing they lost some satosh in the process. When training, what are you mostly concerned about, to gain more profit in bitcoin or gain more in usd dollar without minding if you lost some Satoshi value?.
It depends on trader's preference, for people who want to cashout profits into fiat in short time is good to go with USD value but one who are interested in investing back the profits made as their capital again should choose bitcoin value or satoshi value for their trading pairs.
When I am doing day trading I consider the trader and offers based on fiat value only.