I trade with the EURUSD pair because it's volatile in the market, and with a good strategy, consistent profit is possible.
These are tough times for forex long-term trend-following. I'm taking a break until these resume across the main pairs.
Over the past few years, I rarely day trade currency futures. There are other much better things to trade. A decade ago, there were currency wars and those were very good times to trade currency futures. Some traders even claimed to earn $$$ by being blindfolded.
I mainly trade EUR/USD. This is the most liquid pair, it has moderate volatility, which reduces the risk of frequent stop-losses and very low spreads (for example, my broker fxopen has a spread of only 1-2 points). Therefore, it is profitable and comfortable for me to trade this pair.