That's a good question. One would need to think across the range of federal and provincial benefits and programs. I'm thinking of income-tested benefits delivered through the tax system.
As you mentioned, that's part of the reason that the Canada child benefit is delivered on the 20th of the month. If you look at the GST credit, it's quarterly on the first month of every quarter. I'm not sure how much of a strategy I can claim is behind it, but there is some spacing. I don't know what answer others would have.