In scientific terms, the least count is defined as the highest degree of accuracy of measurement.
For the Canadian Currency, the least count has been recently raised to the nickel following the withdrawal of the penny.
Imagine handed an invoice or a sale receipt for a sum of 10.843 knowing fully well the 3rd digit after the decimal is unnecessary. It is fairly clear that the addition of taxes above the sale price should end in a number which is payable by cash. Currently, seeing even 10.84 is meaningless as opposed to 10.85.
So here we are with a raised least count and always ending up either being short changed or payed a bit more for what we see on the receipt. While it may not bother an individual even if the day is marked for a shopping spree, I am positive it would bring a lot of headache to merchants of goods and services who may try to balance their accounts at the end of the day and always receive a difference between the actual amounts realized vis-a-vis what is shown on the receipts.
It helps to keep things clear by simply omitting the penny in all receipts. If all receipts and invoices show the final amount rounded to the nearest nickel, I am sure neither a customer may feel short-changed nor a supplier have to satisfy himself every day that his cash is being well handled.