Again that article doesn’t actually cite anything and is very opinionated and vague. Basically saying “trust me bro”. Even if those big businesses are saving I very much doubt those savings are going to pass on to the little guy. They breeze right past this part.

What kinds of costs were considered? They included out-of-pocket payments for physical changes in things: for example, modifying scales or buying new ones, altering gasoline pumps, adjusting or replacing machinery, repainting highway signs, rewriting plans and specifications. They also involved intangibles, such as having to learn new words and how to use them, having to work more slowly for a while in order to avoid mistakes, and having to do arithmetic in order to understand an item in the newspaper.

Every tradesman would have to buy all new tools for the metric standard. They’d have to account for mistakes when doing conversions between the new metric stuff when working with an existing construction or carry two sets of tools with them. A corporation might be able to absorb those costs easily enough but for an individual that’s going to take a much larger bite out of them.