Except electricity is billed in kWh, everything consumes power on kw, and kWh is by far a more intuitive unit of consumption once you get past the basic of educational step of explaining 1 kw for 1 hr = 1 kWh.
As an EE I much prefer kWh, though its not all that hard to add the factor 3.6 if you really want MJ
Most people aren’t engineers and the idea of watt-hours per hour makes eyes glaze over; miles per gallon vs… watt-hours-per-mile ? Nah that is confusing too. Miles per MJ and how many MJ does the car have is nice and clean.
As an EE I much prefer kWh, though its not all that hard to add the factor 3.6 if you really want MJ