Yeah, the canceling out thing is hard to ignore. UoA and deep liquidity (hence easy arbitrage) is a tough thing to break from. Was thinking other day though, that if you stretch out the time between trades, then you can more clearly see how it's different trading pairs, since usd price for things fluctuates a good deal over even relatively short times. I think it's a gradually then suddenly thing in the end. Maybe we slowly chip away at USD UoA as markets freeze up here and there, and people use BTC (or xmr..sigh) increasingly.