For customers who want to withdraw to USD bank accounts NBT would indeed be the better choice.
The shapeshift “integration” would still work - just with converting it to NBT and depositing NBT at bitwala.
As the NBT(/USD,BTC) liquidity is guaranteed by Nu, bitwala might consider NBT to receive funds in addition to receiving BTC.
After you gave it a try, would you consider suggesting this improvement to their service?