I think there are two aspects, one being the difficulty of getting any standard defined and accepted, and the other whether the standard reflects an arbitrary set or provides practical metrics for the product.
Re unit pricing, and the venerable tea bag argument, ‘we’ covered aspects of that [in another thread]((How easy is it to use unit pricing in the supermarket? - #12 by PhilT) that was also previously linked above.
Some things just do not lend themselves to single meaningful units so whatever is picked will be arbitrary for some and meaningful for others. Is picking one going to be confusing, or providing the information for each group? I vote to specify both where it is clearly applicable such as tea bags, but not where it is subjective like ‘numbers of washes’ where there is no consumer concept of ‘the standard wash’ and machines come in 7, 8, 9, 10kg and more capacities making the number of washes per weight quite slippery.
I trust those examples made a point regarding real utility of unit pricing, not just the implementation.
