It's strictly a matter of convenience. CEC does not require that 'down' mean 'off.'
You'll also see a number of other differences, especially regarding specific GFCI and AFCI requirements. You'll often hear that it's required to remove / disconnect knob&tube. You'll hear of a limit on the number of lights or receptacles on a circuit.
You'll learn that it's OK to wire-nut aluminum to copper using what appear to be ordinary wirenuts (specific nuts are approved for the use). You'll see new FPE-like panels being installed. Panel-mounted surge protecters are described as 'necessary.'
And I'm sure there are other differences ...
