In physics, in practice you either state the number in exponential notation and don't care abut it or for brevity introduce a more appropriate unit: barns (10⁻²⁸ m²) and electronvolts (10⁻¹⁹ J) in nuclear physics or solar mass (~10³⁰ kg) in astrophysics, etc.
But from Wikipedia:
> In the United Kingdom ... Demand for electricity in 2014 was 34.42 GW on average (301.7 TWh over the year) coming from a total electricity generation of 335.0 TWh.
We aren't there yet for power:
> The synchronous grid of Continental Europe is the largest synchronous electrical grid (by connected power) in the world. ... In 2009, 667 GW of production capacity was connected to the grid
CERN is at TeV ranges so yes, even in different units we use high prefixes. Might not come up in your every day small talk but they are used.
Why are these not serious usages? They are concepts that need to be communicated, that's what words are for.