As of this writing this algo is ranked #1 and is in the top 1% of the community.

It's a crypto algo. GDAX charges high fees for 'takers', and there is no fee modelling. It will have to be appropriately converted to limit orders in order to take advantage of GDAX's zero fee for 'makers' fee model in order to actually be useful. Slippage is low on GDAX for the instruments in question so that shouldn't have too much of an impact.