If the EmDrive Works…

… it still might not be that useful.

At 1.2 mN/kW and 4300 W/kg, that's an acceleration of $5.16\times10^{-4}~\text{m/s}^2$.

A bit slow. It can go 80 million km (the distance between the orbits of Earth and Mars) in about 9 months.

The above needs a correction.