I use Watts on the page where I aggregate my results[1], but since most USB-related projects measure mA (and most battery ratings use mAh), I use the same convention as a default, since 5V can be assumed in all cases.
It wasn't intended to be an excuse for not using "correct" terminology or units.
The reason that these terminology and units were used by OP was because at a fixed voltage it is common for engineers to think about current instead of watts... even when their aiming to reduce power.
I'm not sure of the exact reason for this, but I suspect that it's because:
a) Measuring current is a more fundamental function of instruments. Quite a lot don't even measure power. So talking about current instead of power, even when you're aim is to reduce power, makes for a smoother process from a practical sense.
b) Batteries are usually measured in mAh. At lower power/currents you're usually using a linear regulator and therefore dividing mAh by mA is a very important measure. So you often keep everything in mA.
[1] https://github.com/geerlingguy/raspberry-pi-dramble/wiki/Pow...