But it works fine for the intended audience and purpose, which is usually to give a very vague idea without assuming any specialized knowledge. If they wanted to enable real reasoning with the data(which they probably should) then they could just give the actual number, in full precision.

I would imagine a lot of this is just an individual thing. Some people make real decisions with mental arithmetic on a regular basis, others almost never encounter math outside of a screen, because apps have taken over a lot of the stuff that used to be done mentally.