I am one of the people who do my calculations in Bitcoin. I started out doing them in dollars but I have switched.
It all has to do with one simple question: Do you believe that Bitcoin (or Ethereum in this case) will be worth more in the future than it is today?
If the answer is yes, then it makes more sense to accumulate BTC/ETH, because every gain you make today can be amplified many times over because of BTC/ETH price rise.
Making 2000$ worth of usd is great and all, but if you made 2000$ worth of Bitcoin I am pretty sure it's going to be worth $10K if you wait a year or so. But, like I said, it all depends on how convinced you are of the long-term successes of Bitcoin and Ethereum. If you think they might fail, then it's better and safer to just take your profits as dollars.
Personally I don't think btc/eth going to fail because now they have huge community behind them.
lol I think that might be my problem. I'm not convinced that any of this will be successful long term. This is all still big gamble in my mind and I'm a bit paranoid at times.