The point is that each of those vectors of exposure carry some obvious context. Which matters a lot: where you are in relation to the radiation matters immensely. Alpha is harmless from without, but deadly within. What are the energies of the decay, and what particles are emitted? Are there secondary/tertiary decays and when? Can the body keep up with the damage? Are we talking sunburns or cancer inducing high energy gamma or high kinetic energy alpha? Nuclear physics earns it's reputation as a complicated science.

Units matter, and context matters. Perhaps we should fear bananas, or use it as a point if reference. Either way, it's a useful, comprehensible comparison, just like the others mentioned. Just think it through, and you don't need to worry about falling for hog wash.