Here in the US, while unit pricing is commonly displayed, I frequently find that a store will use a wide variety of units, thereby negating the ability to easily compare items in this way. For the same type of product I may see cost per ounce, cost per pound, cost per each, cost per dozen, etc. for various sizes and brands. It's maddening, insulting, and probably in most cases malicious.
Yeah, this is insane e.g. I've seen cents/fl.oz, dollars/litre, cents/ml, dollars/unit. For the same product. And yes, totally malicious. Fresh Thyme does this. It's ugly.
Example below. Top row is blurry but bottom row shows “per ounce” price on the bottom right. Tiny print and I imagine barely anyone actually shops that way.
I’m guessing there must be some US requirement for this otherwise I’m not sure why it’s commonplace.
I think the commenter you are responding to does not have enough faith in humanity. Most people I know (anecdotal and biased sampling I know) do check that number when shopping, especially for interchangeable items that don't have a well-know brand such as flour or baking powder.
