That’s why you don’t arbitrarily peg it. You peg it to the NSR/other market so that it recursively affects the true price of NSR. You basically peg NSR/NBT to NSR/USD and it acts as an economic lever for NBT/USD.
For example: If NSR/BTC shows NSR valued at $0.002 and NBT/USD drops to $.5, the peg will be at NSR/NBT=0.002 so that people will burn NBT for NSR because the open market has NSR/NBT at .004. As people sell NSR for BTC, then BTC for NBT, the NSR/NBT price will get lower and the NBT/USD price will get higher.
Edit: I was double counting the NBT/USD factor in my equations; it’s actually simpler this way.
Pegging is useful for day to day operations and in the event of a black swan, where custodians are paid to put orders up against the tide, burning their way back to avoid traveling through a thin buy side.