Because people near Ireland use an obtuse definition of million/billion. Engineering notation is precise and unambiguous.

Arguably, the short scale, not the long scale used in Ireland is obtuse. 12 zeroes for billion and 18 zeroes for trillion, 24 for quadrillion etc is 6n where n is numerical value of Latin prefix, with short scale you've got 3n+3

Nonsense.

> The meaning of the word "million" is common to the short scale and long scale

https://en.wikipedia.org/wiki/1,000,000

If you're going to use the scientific notation for billions, you should just use it for everything. I don't think it's so obtuse anyway, it's exactly how I'd spell that number in code.

I'm just curious what 160 million Euro would mean in Ireland. Can you explain, please?

I think "1 million" means 1e6 everywhere. But the confusion might be because "1 billion" means 1e9 in USA but 1e12 in UK/Ireland. "1 trillion" similarly is 1e12 in USA but 1e18 in UK/Ireland. This is called the short/long scales. It's a headache.

I knew billion was different, but the commenter mentioned million specifically as having a different meaning.