It seems like it would be useful to review the reason for parametric order books.
Imagine we decide to maintain liquidity on an NSR/NBT pair. With very low liquidity, there is a real risk that NuBot will attempt to peg NSR. This isnât possible to maintain, and will result in a loss for anyone attempting to peg NSR. The important question is whether the supported market is creating the price or reacting to it. If most volume in NSR is on a supported NBT pair, then we are making the NSR price, not following the market. That is the problem that parametric order books can address.
With liquid pairs, our own NBT/BTC pair at Poloniex isnât attempting to peg the BTC price, because trading on the pair is dwarfed by Bitcoin trading on other pairs, which determine the price NuBot offers trades at.
Essentially, parametric order books are needed if there is a risk that our supported pairs will have any where near the majority of trading volume for a particular asset. That isnât a risk for BTC, ETH and USD markets, so they should not employ parametric order books.