[Xylakant]

which seems to be the case in switzerland: If you want to apply for swiss citizenship, your name needs to be compatible with ISO-8859-15 because the central registry does not support unicode: https://www.dasmagazin.ch/2016/09/02/ic-bin-kein-schweizer/ (sorry, german only, which seems oddly apt)

[vuanotinn]

That sounds like a good way of keeping undesirable people out without being accused of "racism"

[Grishnakh]

I don't know of any languages that don't have a Latinized written form: Russian, Japanese, Mandarin, Arabic, etc. all have Latinized forms.