Lol, 13 answers, and one of them actually addresses the question. :p
I work as a waitress, Canadian here, eh? It makes absolutely no difference if truth be telt, as long as you know how to round up numbers, which isn’t complicated. And said rounding up will never go higher than 99, so after you do it a few times it’s easy, even if you suck at math, like me.
At first it took a slight bit of getting used to. (I don’t work the cash register) This was mostly due because when this first started, places accepted pennies from customers if they were paying with them, but staff couldn’t give them out as change. And I can barely complain about what little confusion this may have caused, as I started my job some number of weeks after this was put into effect. Now you don’t see pennies anywhere, so the whole thing quickly settled into the norm.