[CydeWeys]

This is just the -re vs -er difference in English spelling between British English and American English, dating back to Webster's reforms in the late 1700s. https://www.learnenglish.de/spelling/spellingrevser.html

Frankly, the -er is better based on actual English pronunciation rules. The -re ending comes from French and is less compatible with how most of the rest of English is pronounced.

And I can't say I've ever been confused by these two different meanings of the word. Can you even come up with an example sentence illustrating ambiguity here?

[Jedd]

Ooh, that first bit suggests you're in danger of suggesting there's a coherent, sensible, set of rules for English ... which I'm sure you don't really subscribe to. Anyone adopting that position as a starting point is going to have a bad day, of course. : )

So, is 'er' better in terms of pronunciation? Perhaps, though I don't think that matters much, as pronunciation varies so wildly based on country, region, education, etc, plus there's so much inconsistency with spelling -> pronunciation within English that I think it's fair to say that ship has long since sailed.

In terms of writing however there's a huge advantage to having words with different meanings have different spellings. I assume I don't have to pitch that idea terribly hard?

For us non-Americans I suspect the frustration boils down to having a recalcitrant nation stubbornly refusing to join the rest of the metric world while simultaneously poisoning the language well of metric unit names everyone else is already using.