It's worth noting that sometimes (incorrect) keyboard maps can get in the way.
If it's a key that you may not often type and one that is often transposed between regions, the fact that the entered char is not shown can lead to frustration.
e.g. " and @ are in different positions in UK vs. US keyboards. So user thinks they are typing @, but " goes into the box.
Meh, takes you like some days to get used to another layout being visible on the keys, while your OS (and brain) actually using another layout.
I've used US keyboard layout since I started programming (my first mentor essentially forced me to switch to it, he was right about it being easier), but throughout the years been using Swedish, Norwegian, British, Spanish and French physical keyboards, never cleanly mapped to the actual layout I've used on the OS, and never been an issue.
The last part though, is a real one, trying to pair program with Spanish programmers always have at least one moment of holding Shift and sliding the finger across all numbers to see where that specific symbol actually is.
On other layouts that isn't enough. For example French keyboards are AZERTY, not QWERTY. and here in Sweden we have å, ä and ö next to the (tall) enter key, instead of the symbols US and UK have.
(Side note: those are not a and o with diacretics, they are entirely separate letters in the alphabets of the Nordic countries, with entirely different sounds.)
The product I make deals with passwords. We’ve had several bugs over the years that came down to Unicode usernames and passwords containing unexpected characters. Solving them was simple, we just had to be sure to get the encoding and character sets right, but as an American it was eye opening to find so many people with the Euro symbol in password strings.
One of the more annoying things I've found moving country is the unavailability of keyboards / laptops with the layout I grew up with. I find it especially annoying as the country I'm from uses a US layout which I naively assumed would be easily available everywhere (and it is available but not without a long delivery and a premium price)
Side note: helping my French housemate with his uni assignments was an experience, none of the symbols were where I expected them to be