Great suggestion Jason!
The problem is that the smaller the order gets, the larger the network transaction fee becomes compared to the size of the order.
For example, right now a Bitcoin transaction has a network fee of 0.0002 BTC, or $1.00 NZD, regardless of the size of that transaction.
In a $1000 order, that fee is 0.1% - effectively immaterial.
In a $100 order, that fee is 1.0% of the order. Not the best, but not terrible.
In a $10 order, that fee is 10% of the order!
So while we can easily sell less than $100 minimum, we’re concerned that people will be unhappy with such a large percentage of their order going to the network transaction fees.