Yeah excellent point. When presenting numbers for reading/interpretation then talking in terms of cubes with a certain side length has to be the easiest to interpret. Its important to be specific about the units and not say "5 metres cubed" because that will just lead to confusion with m^3 (already confusing to be fair!).
An alternative is using "known" points of reference like Olympic swimming pools, the Sistine Chapel etc (similar to "an area the size of Belgium"). But that risks getting absurd.
An alternative is using "known" points of reference like Olympic swimming pools, the Sistine Chapel etc (similar to "an area the size of Belgium"). But that risks getting absurd.