It's just all about where the strong trend holds. USD is a major currency in all, it can be both strong and weak. Right now it looks like USD is right in the middle of BTCUSD and USDCAD. They both are moving up.
paper trading competition is pointless, you can´t even send a trade with pine script. What´s the point? we all know that unless you can repeat the very same trade a 1000 when you win it might just be luck